Tests: switched to using f-strings.

Previously, it was necessary to support older versions of Python for
compatibility.  F-strings were released in Python 3.6.  Python 3.5 was
marked as unsupported by the end of 2020, so now it's possible to start
using f-strings safely for better readability and performance.

test/conftest.py

@@ -107,7 +107,7 @@ def pytest_configure(config):
     option.current_dir = os.path.abspath(
         os.path.join(os.path.dirname(__file__), os.pardir)
     )
-    option.test_dir = option.current_dir + '/test'
+    option.test_dir = f'{option.current_dir}/test'
     option.architecture = platform.architecture()[0]
     option.system = platform.system()
 
@@ -148,8 +148,8 @@ def pytest_generate_tests(metafunc):
 
         for version in versions:
             option.generated_tests[
-                metafunc.function.__name__ + '[{}]'.format(version)
-            ] = (type + ' ' + version)
+                f'{metafunc.function.__name__} [{version}]'
+            ] = f'{type} {version}'
 
     # take available module from option and generate tests for each version
 
@@ -161,18 +161,17 @@ def pytest_generate_tests(metafunc):
                 generate_tests(available_versions)
 
             elif prereq_version == 'any':
-                option.generated_tests[metafunc.function.__name__] = (
-                    type + ' ' + available_versions[0]
-                )
+                option.generated_tests[
+                    metafunc.function.__name__
+                ] = f'{type} {available_versions[0]}'
             elif callable(prereq_version):
                 generate_tests(list(filter(prereq_version, available_versions)))
 
             else:
                 raise ValueError(
-                    """
-Unexpected prerequisite version "%s" for module "%s" in %s.
-'all', 'any' or callable expected."""
-                    % (str(prereq_version), module, str(cls))
+                    f'''
+Unexpected prerequisite version "{prereq_version}" for module "{module}" in
+{cls}. 'all', 'any' or callable expected.'''
                 )
 
 
@@ -225,7 +224,7 @@ def pytest_sessionstart(session):
     check_isolation()
     check_unix_abstract()
 
-    _clear_conf(unit['temp_dir'] + '/control.unit.sock')
+    _clear_conf(f'{unit["temp_dir"]}/control.unit.sock')
 
     unit_stop()
 
@@ -244,7 +243,7 @@ def pytest_runtest_makereport(item, call):
     # set a report attribute for each phase of a call, which can
     # be "setup", "call", "teardown"
 
-    setattr(item, "rep_" + rep.when, rep)
+    setattr(item, f'rep_{rep.when}', rep)
 
 
 @pytest.fixture(scope='class', autouse=True)
@@ -264,7 +263,7 @@ def check_prerequisites(request):
             missed.append(module)
 
     if missed:
-        pytest.skip('Unit has no ' + ', '.join(missed) + ' module(s)')
+        pytest.skip(f'Unit has no {", ".join(missed)} module(s)')
 
     # check features
 
@@ -278,7 +277,7 @@ def check_prerequisites(request):
             missed.append(feature)
 
     if missed:
-        pytest.skip(', '.join(missed) + ' feature(s) not supported')
+        pytest.skip(f'{", ".join(missed)} feature(s) not supported')
 
 
 @pytest.fixture(autouse=True)
@@ -316,7 +315,7 @@ def run(request):
     # clean temp_dir before the next test
 
     if not option.restart:
-        _clear_conf(unit['temp_dir'] + '/control.unit.sock', log=log)
+        _clear_conf(f'{unit["temp_dir"]}/control.unit.sock', log=log)
 
         if is_findmnt and not waitforunmount(unit['temp_dir'], timeout=600):
             exit('Could not unmount some filesystems in tmp dir.')
@@ -374,8 +373,8 @@ def unit_run(state_dir=None):
     if not option.restart and 'unitd' in unit_instance:
         return unit_instance
 
-    build_dir = option.current_dir + '/build'
-    unitd = build_dir + '/unitd'
+    build_dir = f'{option.current_dir}/build'
+    unitd = f'{build_dir}/unitd'
 
     if not os.path.isfile(unitd):
         exit('Could not find unit')
@@ -386,10 +385,12 @@ def unit_run(state_dir=None):
     if oct(stat.S_IMODE(os.stat(build_dir).st_mode)) != '0o777':
         public_dir(build_dir)
 
-    state = temp_dir + '/state' if state_dir is None else state_dir
+    state = f'{temp_dir}/state' if state_dir is None else state_dir
     if not os.path.isdir(state):
         os.mkdir(state)
 
+    control_sock = f'{temp_dir}/control.unit.sock'
+
     unitd_args = [
         unitd,
         '--no-daemon',
@@ -398,11 +399,11 @@ def unit_run(state_dir=None):
         '--libstatedir',
         state,
         '--pid',
-        temp_dir + '/unit.pid',
+        f'{temp_dir}/unit.pid',
         '--log',
-        temp_dir + '/unit.log',
+        f'{temp_dir}/unit.log',
         '--control',
-        'unix:' + temp_dir + '/control.unit.sock',
+        f'unix:{temp_dir}/control.unit.sock',
         '--tmpdir',
         temp_dir,
     ]
@@ -410,26 +411,26 @@ def unit_run(state_dir=None):
     if option.user:
         unitd_args.extend(['--user', option.user])
 
-    with open(temp_dir + '/unit.log', 'w') as log:
+    with open(f'{temp_dir}/unit.log', 'w') as log:
         unit_instance['process'] = subprocess.Popen(unitd_args, stderr=log)
 
     Log.temp_dir = temp_dir
 
-    if not waitforfiles(temp_dir + '/control.unit.sock'):
+    if not waitforfiles(control_sock):
         _print_log()
         exit('Could not start unit')
 
     unit_instance['temp_dir'] = temp_dir
-    unit_instance['control_sock'] = temp_dir + '/control.unit.sock'
+    unit_instance['control_sock'] = control_sock
     unit_instance['unitd'] = unitd
 
     option.temp_dir = temp_dir
 
-    with open(temp_dir + '/unit.pid', 'r') as f:
+    with open(f'{temp_dir}/unit.pid', 'r') as f:
         unit_instance['pid'] = f.read().rstrip()
 
     if state_dir is None:
-        _clear_conf(unit_instance['temp_dir'] + '/control.unit.sock')
+        _clear_conf(control_sock)
 
     _fds_info['main']['fds'] = _count_fds(unit_instance['pid'])
 
@@ -473,7 +474,7 @@ def unit_stop():
     try:
         retcode = p.wait(15)
         if retcode:
-            return 'Child process terminated with code ' + str(retcode)
+            return f'Child process terminated with code {retcode}'
 
     except KeyboardInterrupt:
         p.kill()
@@ -518,7 +519,7 @@ def _check_alerts(*, log=None):
 def _print_log(log=None):
     path = Log.get_path()
 
-    print('Path to unit.log:\n' + path + '\n')
+    print(f'Path to unit.log:\n{path}\n')
 
     if option.print_log:
         os.set_blocking(sys.stdout.fileno(), True)
@@ -551,11 +552,11 @@ def _clear_conf(sock, *, log=None):
         ).keys()
 
     except json.JSONDecodeError:
-        pytest.fail('Can\'t parse certificates list.')
+        pytest.fail("Can't parse certificates list.")
 
     for cert in certs:
         resp = http.delete(
-            url='/certificates/' + cert,
+            url=f'/certificates/{cert}',
             sock_type='unix',
             addr=sock,
         )['body']
@@ -595,17 +596,14 @@ def _check_processes():
     out = [
         l
         for l in out
-        if re.search(router_pid + r'\s+' + unit_pid + r'.*unit: router', l)
-        is None
+        if re.search(fr'{router_pid}\s+{unit_pid}.*unit: router', l) is None
     ]
     assert len(out) == 1, 'one router'
 
     out = [
         l
         for l in out
-        if re.search(
-            controller_pid + r'\s+' + unit_pid + r'.*unit: controller', l
-        )
+        if re.search(fr'{controller_pid}\s+{unit_pid}.*unit: controller', l)
         is None
     ]
     assert len(out) == 0, 'one controller'
@@ -646,18 +644,16 @@ def _check_fds(*, log=None):
             ps['fds'] += fds_diff
 
             if not option.restart:
-                assert ps['pid'] == ps_pid, 'same pid %s' % name
+                assert ps['pid'] == ps_pid, f'same pid {name}'
 
-            assert fds_diff <= option.fds_threshold, (
-                'descriptors leak %s' % name
-            )
+            assert fds_diff <= option.fds_threshold, f'descriptors leak {name}'
 
         else:
             ps['fds'] = _count_fds(ps['pid'])
 
 
 def _count_fds(pid):
-    procfile = '/proc/%s/fd' % pid
+    procfile = f'/proc/{pid}/fd'
     if os.path.isdir(procfile):
         return len(os.listdir(procfile))
 
@@ -712,14 +708,12 @@ def stop_processes():
 
 def pid_by_name(name):
     output = subprocess.check_output(['ps', 'ax', '-O', 'ppid']).decode()
-    m = re.search(
-        r'\s*(\d+)\s*' + str(unit_instance['pid']) + r'.*' + name, output
-    )
+    m = re.search(fr'\s*(\d+)\s*{unit_instance["pid"]}.*{name}', output)
     return None if m is None else m.group(1)
 
 
 def find_proc(name, ps_output):
-    return re.findall(str(unit_instance['pid']) + r'.*' + name, ps_output)
+    return re.findall(f'{unit_instance["pid"]}.*{name}', ps_output)
 
 
 @pytest.fixture()
@@ -762,7 +756,7 @@ def unit_pid(request):
 
 def pytest_sessionfinish(session):
     if not option.restart and option.save_log:
-        print('Path to unit.log:\n' + Log.get_path() + '\n')
+        print(f'Path to unit.log:\n{Log.get_path()}\n')
 
     option.restart = True
 

test/python/environment/wsgi.py

@@ -2,13 +2,10 @@ import os
 
 
 def application(env, start_response):
-    body = ''
     vars = env.get('HTTP_X_VARIABLES').split(',')
 
-    for var in vars:
-        if var in os.environ:
-            body += str(os.environ[var]) + ','
-
+    body = ','.join([str(os.environ[var]) for var in vars if var in os.environ])
     body = body.encode()
+
     start_response('200', [('Content-Length', str(len(body)))])
     return body

test/python/input_readline_size/wsgi.py

@@ -9,7 +9,7 @@ def application(environ, start_response):
         body.append(l)
 
         if len(l) > 9:
-            body.append(b'len(l) > 9: ' + l)
+            body.append(f'len(l) > 9: {l}'.encode())
             break
 
     start_response('200', [('X-Lines-Count', str(len(body)))])

test/python/lifespan/empty/asgi.py

@@ -3,17 +3,17 @@ import os
 
 async def handler(prefix, scope, receive, send):
     if scope['type'] == 'lifespan':
-        with open(prefix + 'version', 'w+') as f:
+        with open(f'{prefix}version', 'w+') as f:
             f.write(
-                scope['asgi']['version'] + ' ' + scope['asgi']['spec_version']
+                f"{scope['asgi']['version']} {scope['asgi']['spec_version']}"
             )
         while True:
             message = await receive()
             if message['type'] == 'lifespan.startup':
-                os.remove(prefix + 'startup')
+                os.remove(f'{prefix}startup')
                 await send({'type': 'lifespan.startup.complete'})
             elif message['type'] == 'lifespan.shutdown':
-                os.remove(prefix + 'shutdown')
+                os.remove(f'{prefix}shutdown')
                 await send({'type': 'lifespan.shutdown.complete'})
                 return
 
@@ -22,7 +22,9 @@ async def handler(prefix, scope, receive, send):
             {
                 'type': 'http.response.start',
                 'status': 204,
-                'headers': [(b'content-length', b'0'),],
+                'headers': [
+                    (b'content-length', b'0'),
+                ],
             }
         )
 

test/python/targets/wsgi.py

@@ -9,9 +9,6 @@ def wsgi_target_b(env, start_response):
 
 
 def wsgi_target_prefix(env, start_response):
-    data = u'%s %s' % (
-        env.get('SCRIPT_NAME', 'No Script Name'),
-        env['PATH_INFO'],
-    )
-    start_response('200', [('Content-Length', '%d' % len(data))])
+    data = f"{env.get('SCRIPT_NAME', 'No Script Name')} {env['PATH_INFO']}"
+    start_response('200', [('Content-Length', f'{data}')])
     return [data.encode('utf-8')]

test/python/threading/asgi.py

@@ -11,9 +11,7 @@ class Foo(threading.Thread):
         threading.Thread.__init__(self)
 
     def log_index(self, index):
-        sys.stderr.write(
-            "(" + str(index) + ") Thread: " + str(self.__x) + "\n"
-        )
+        sys.stderr.write(f'({index}) Thread: {self.__x}\n')
         sys.stderr.flush()
 
     def run(self):

test/python/threading/wsgi.py

@@ -11,9 +11,7 @@ class Foo(threading.Thread):
         threading.Thread.__init__(self)
 
     def log_index(self, index):
-        sys.stderr.write(
-            "(" + str(index) + ") Thread: " + str(self.__x) + "\n"
-        )
+        sys.stderr.write(f'({index}) Thread: {self.__x}\n')
         sys.stderr.flush()
 
     def run(self):

test/python/unicode/wsgi.py

@@ -1,7 +1,7 @@
 def application(environ, start_response):
     temp_dir = environ.get('HTTP_TEMP_DIR')
 
-    with open(temp_dir + '/tempfile', 'w') as f:
+    with open(f'{temp_dir}/tempfile', 'w') as f:
         f.write('\u26a0\ufe0f')
 
     start_response('200', [('Content-Length', '0')])

test/test_access_log.py

@@ -12,13 +12,13 @@ class TestAccessLog(TestApplicationPython):
         super().load(script)
 
         assert 'success' in self.conf(
-            '"' + option.temp_dir + '/access.log"', 'access_log'
+            f'"{option.temp_dir}/access.log"', 'access_log'
         ), 'access_log configure'
 
     def set_format(self, format):
         assert 'success' in self.conf(
             {
-                'path': option.temp_dir + '/access.log',
+                'path': f'{option.temp_dir}/access.log',
                 'format': format,
             },
             'access_log',
@@ -103,13 +103,13 @@ Connection: close
             is not None
         ), 'ipv6'
 
-    def test_access_log_unix(self):
+    def test_access_log_unix(self, temp_dir):
         self.load('empty')
 
-        addr = option.temp_dir + '/sock'
+        addr = f'{temp_dir}/sock'
 
         assert 'success' in self.conf(
-            {"unix:" + addr: {"pass": "applications/empty"}}, 'listeners'
+            {f'unix:{addr}': {"pass": "applications/empty"}}, 'listeners'
         )
 
         self.get(sock_type='unix', addr=addr)
@@ -248,14 +248,12 @@ Connection: close
 
         assert self.search_in_log(r'/delete', 'access.log') is None, 'delete'
 
-    def test_access_log_change(self):
+    def test_access_log_change(self, temp_dir):
         self.load('empty')
 
         self.get()
 
-        assert 'success' in self.conf(
-            '"' + option.temp_dir + '/new.log"', 'access_log'
-        )
+        assert 'success' in self.conf(f'"{temp_dir}/new.log"', 'access_log')
 
         self.get()
 
@@ -286,19 +284,20 @@ Connection: close
         body = '0123456789' * 50
         self.post(url='/bbs', body=body, read_timeout=1)
         assert (
-            self.wait_for_record(r'^\/bbs ' + str(len(body)) + r'$') is not None
+            self.wait_for_record(fr'^\/bbs {len(body)}$') is not None
         ), '$body_bytes_sent'
 
-    def test_access_log_incorrect(self, skip_alert):
+    def test_access_log_incorrect(self, temp_dir, skip_alert):
         skip_alert(r'failed to apply new conf')
 
         assert 'error' in self.conf(
-            option.temp_dir + '/blah/access.log' 'access_log/path',
+            f'{option.temp_dir}/blah/access.log',
+            'access_log/path',
         ), 'access_log path incorrect'
 
         assert 'error' in self.conf(
             {
-                'path': option.temp_dir + '/access.log',
+                'path': f'{temp_dir}/access.log',
                 'format': '$remote_add',
             },
             'access_log',

test/test_asgi_application.py

@@ -20,17 +20,16 @@ class TestASGIApplication(TestApplicationPython):
         body = 'Test body string.'
 
         resp = self.http(
-            b"""POST / HTTP/1.1
+            f"""POST / HTTP/1.1
 Host: localhost
-Content-Length: %d
+Content-Length: {len(body)}
 Custom-Header: blah
 Custom-hEader: Blah
 Content-Type: text/html
 Connection: close
 custom-header: BLAH
 
-%s"""
-            % (len(body), body.encode()),
+{body}""".encode(),
             raw=True,
         )
 
@@ -63,9 +62,9 @@ custom-header: BLAH
     def test_asgi_application_unix(self, temp_dir):
         self.load('empty')
 
-        addr = temp_dir + '/sock'
+        addr = f'{temp_dir}/sock'
         assert 'success' in self.conf(
-            {"unix:" + addr: {"pass": "applications/empty"}}, 'listeners'
+            {f"unix:{addr}": {"pass": "applications/empty"}}, 'listeners'
         )
 
         assert self.get(sock_type='unix', addr=addr)['status'] == 200
@@ -83,7 +82,7 @@ custom-header: BLAH
         self.load('prefix', prefix='/api/rest')
 
         def set_prefix(prefix):
-            self.conf('"' + prefix + '"', 'applications/prefix/prefix')
+            self.conf(f'"{prefix}"', 'applications/prefix/prefix')
 
         def check_prefix(url, prefix):
             resp = self.get(url=url)
@@ -190,7 +189,7 @@ custom-header: BLAH
         max_body_size = 12 * 1024 * 1024
 
         assert 'success' in self.conf(
-            '{"http":{"max_body_size": ' + str(max_body_size) + ' }}',
+            f'{{"http":{{"max_body_size": {max_body_size} }}}}',
             'settings',
         )
 

test/test_asgi_application_unix_abstract.py

@@ -16,7 +16,7 @@ class TestASGIApplicationUnixAbstract(TestApplicationPython):
 
         addr = '\0sock'
         assert 'success' in self.conf(
-            {"unix:@" + addr[1:]: {"pass": "applications/empty"}},
+            {f"unix:@{addr[1:]}": {"pass": "applications/empty"}},
             'listeners',
         )
 

test/test_asgi_lifespan.py

@@ -15,25 +15,25 @@ class TestASGILifespan(TestApplicationPython):
     load_module = 'asgi'
 
     def setup_cookies(self, prefix):
-        base_dir = option.test_dir + '/python/lifespan/empty'
+        base_dir = f'{option.test_dir}/python/lifespan/empty'
 
         os.chmod(base_dir, 0o777)
 
         for name in ['startup', 'shutdown', 'version']:
-            path = option.test_dir + '/python/lifespan/empty/' + prefix + name
+            path = f'{option.test_dir}/python/lifespan/empty/{prefix}{name}'
             open(path, 'a').close()
             os.chmod(path, 0o777)
 
     def assert_cookies(self, prefix):
         for name in ['startup', 'shutdown']:
-            path = option.test_dir + '/python/lifespan/empty/' + prefix + name
+            path = f'{option.test_dir}/python/lifespan/empty/{prefix}{name}'
             exists = os.path.isfile(path)
             if exists:
                 os.remove(path)
 
             assert not exists, name
 
-        path = option.test_dir + '/python/lifespan/empty/' + prefix + 'version'
+        path = f'{option.test_dir}/python/lifespan/empty/{prefix}version'
 
         with open(path, 'r') as f:
             version = f.read()
@@ -54,6 +54,8 @@ class TestASGILifespan(TestApplicationPython):
         self.assert_cookies('')
 
     def test_asgi_lifespan_targets(self):
+        path = f'{option.test_dir}/python/lifespan/empty'
+
         assert 'success' in self.conf(
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
@@ -71,9 +73,8 @@ class TestASGILifespan(TestApplicationPython):
                     "targets": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "working_directory": option.test_dir
-                        + "/python/lifespan/empty",
-                        "path": option.test_dir + '/python/lifespan/empty',
+                        "working_directory": path,
+                        "path": path,
                         "targets": {
                             "1": {"module": "asgi", "callable": "application"},
                             "2": {

test/test_asgi_targets.py

@@ -14,6 +14,8 @@ class TestASGITargets(TestApplicationPython):
 
     @pytest.fixture(autouse=True)
     def setup_method_fixture(self):
+        path = f'{option.test_dir}/python/targets/'
+
         assert 'success' in self.conf(
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
@@ -31,9 +33,8 @@ class TestASGITargets(TestApplicationPython):
                     "targets": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "working_directory": option.test_dir
-                        + "/python/targets/",
-                        "path": option.test_dir + '/python/targets/',
+                        "working_directory": path,
+                        "path": path,
                         "protocol": "asgi",
                         "targets": {
                             "1": {

test/test_asgi_websockets.py

@@ -151,7 +151,7 @@ class TestASGIWebsockets(TestApplicationPython):
 
         frame = self.ws.frame_read(sock)
 
-        assert message + ' ' + message == frame['data'].decode(
+        assert f'{message} {message}' == frame['data'].decode(
             'utf-8'
         ), 'mirror framing'
 
@@ -527,21 +527,21 @@ class TestASGIWebsockets(TestApplicationPython):
         _, sock, _ = self.ws.upgrade()
 
         for i in range(0, 10):
-            self.ws.frame_write(sock, self.ws.OP_PING, 'payload-%d' % i)
+            self.ws.frame_write(sock, self.ws.OP_PING, f'payload-{i}')
 
         for i in range(0, 10):
             frame = self.ws.frame_read(sock)
-            self.check_frame(frame, True, self.ws.OP_PONG, 'payload-%d' % i)
+            self.check_frame(frame, True, self.ws.OP_PONG, f'payload-{i}')
 
         # 2_11
 
         for i in range(0, 10):
             opcode = self.ws.OP_PING
-            self.ws.frame_write(sock, opcode, 'payload-%d' % i, chopsize=1)
+            self.ws.frame_write(sock, opcode, f'payload-{i}', chopsize=1)
 
         for i in range(0, 10):
             frame = self.ws.frame_read(sock)
-            self.check_frame(frame, True, self.ws.OP_PONG, 'payload-%d' % i)
+            self.check_frame(frame, True, self.ws.OP_PONG, f'payload-{i}')
 
         self.close_connection(sock)
 

test/test_client_ip.py

@@ -16,9 +16,7 @@ class TestClientIP(TestApplicationPython):
                     "client_ip": options,
                     "pass": "applications/client_ip",
                 },
-                "unix:"
-                + option.temp_dir
-                + "/sock": {
+                f"unix:{option.temp_dir}/sock": {
                     "client_ip": options,
                     "pass": "applications/client_ip",
                 },
@@ -30,7 +28,7 @@ class TestClientIP(TestApplicationPython):
         address = {
             'ipv4': ('127.0.0.1', 7081),
             'ipv6': ('::1', 7082),
-            'unix': (option.temp_dir + '/sock', None),
+            'unix': (f'{option.temp_dir}/sock', None),
         }
         (addr, port) = address[sock_type]
 

test/test_configuration.py

@@ -283,7 +283,7 @@ class TestConfiguration(TestControl):
 
         assert 'success' in self.conf(
             {
-                "listeners": {"*:7080": {"pass": "applications/" + name}},
+                "listeners": {"*:7080": {"pass": f"applications/{name}"}},
                 "applications": {
                     name: {
                         "type": "python",
@@ -301,8 +301,7 @@ class TestConfiguration(TestControl):
 
         conf = {
             "applications": {
-                "app-"
-                + str(a): {
+                f"app-{a}": {
                     "type": "python",
                     "processes": {"spare": 0},
                     "path": "/app",
@@ -311,7 +310,7 @@ class TestConfiguration(TestControl):
                 for a in range(apps)
             },
             "listeners": {
-                "*:" + str(7000 + a): {"pass": "applications/app-" + str(a)}
+                f"*:{(7000 + a)}": {"pass": f"applications/app-{a}"}
                 for a in range(apps)
             },
         }
@@ -407,8 +406,7 @@ class TestConfiguration(TestControl):
     def test_json_application_many2(self):
         conf = {
             "applications": {
-                "app-"
-                + str(a): {
+                f"app-{a}": {
                     "type": "python",
                     "processes": {"spare": 0},
                     "path": "/app",

test/test_go_application.py

@@ -139,15 +139,15 @@ class TestGoApplication(TestApplicationGo):
         self.load('command_line_arguments')
 
         arg1 = '--cc=gcc-7.2.0'
-        arg2 = '--cc-opt=\'-O0 -DNXT_DEBUG_MEMORY=1 -fsanitize=address\''
+        arg2 = "--cc-opt='-O0 -DNXT_DEBUG_MEMORY=1 -fsanitize=address'"
         arg3 = '--debug'
 
         assert 'success' in self.conf(
-            '["' + arg1 + '", "' + arg2 + '", "' + arg3 + '"]',
+            f'["{arg1}", "{arg2}", "{arg3}"]',
             'applications/command_line_arguments/arguments',
         )
 
-        assert self.get()['body'] == arg1 + ',' + arg2 + ',' + arg3, 'arguments'
+        assert self.get()['body'] == f'{arg1},{arg2},{arg3}', 'arguments'
 
     def test_go_application_command_line_arguments_change(self):
         self.load('command_line_arguments')

test/test_go_isolation.py

@@ -37,7 +37,7 @@ class TestGoIsolation(TestApplicationGo):
 
         for ns, ns_value in option.available['features']['isolation'].items():
             if ns.upper() in obj['NS']:
-                assert obj['NS'][ns.upper()] == ns_value, '%s match' % ns
+                assert obj['NS'][ns.upper()] == ns_value, f'{ns} match'
 
     def test_isolation_unpriv_user(self, is_su):
         if not self.isolation_key('unprivileged_userns_clone'):
@@ -60,7 +60,7 @@ class TestGoIsolation(TestApplicationGo):
 
         # unprivileged unit map itself to nobody in the container by default
         assert obj['UID'] == nobody_uid, 'uid of nobody'
-        assert obj['GID'] == nogroup_gid, 'gid of %s' % nogroup
+        assert obj['GID'] == nogroup_gid, f'gid of {nogroup}'
 
         self.load(
             'ns_inspect',
@@ -200,7 +200,7 @@ class TestGoIsolation(TestApplicationGo):
                 assert (
                     obj['NS'][ns.upper()]
                     == option.available['features']['isolation'][ns]
-                ), ('%s match' % ns)
+                ), f'{ns} match'
 
         assert obj['NS']['MNT'] != getns('mnt'), 'mnt set'
         assert obj['NS']['USER'] != getns('user'), 'user set'
@@ -260,7 +260,7 @@ class TestGoIsolation(TestApplicationGo):
                 assert (
                     obj['NS'][ns.upper()]
                     == option.available['features']['isolation'][ns]
-                ), ('%s match' % ns)
+                ), f'{ns} match'
 
     def test_go_isolation_rootfs_container(self, is_su, temp_dir):
         if not is_su:

test/test_http_header.py

@@ -107,7 +107,7 @@ class TestHTTPHeader(TestApplicationPython):
         resp = self.get(
             headers={
                 'Host': 'localhost',
-                'Custom-Header': r'(),/:;<=>?@[\]{}\t !#$%&\'*+-.^_`|~',
+                'Custom-Header': r"(),/:;<=>?@[\]{}\t !#$%&'*+-.^_`|~",
                 'Connection': 'close',
             }
         )
@@ -115,7 +115,7 @@ class TestHTTPHeader(TestApplicationPython):
         assert resp['status'] == 200, 'value chars status'
         assert (
             resp['headers']['Custom-Header']
-            == r'(),/:;<=>?@[\]{}\t !#$%&\'*+-.^_`|~'
+            == r"(),/:;<=>?@[\]{}\t !#$%&'*+-.^_`|~"
         ), 'value chars custom header'
 
     def test_http_header_value_chars_edge(self):

test/test_java_application.py

@@ -24,9 +24,9 @@ class TestJavaApplication(TestApplicationJava):
                     "app": {
                         "type": self.get_application_type(),
                         "processes": 1,
-                        "working_directory": option.test_dir + "/java/empty",
-                        "webapp": temp_dir + "/java",
-                        "unit_jars": temp_dir + "/no_such_dir",
+                        "working_directory": f"{option.test_dir}/java/empty",
+                        "webapp": f"{temp_dir}/java",
+                        "unit_jars": f"{temp_dir}/no_such_dir",
                     }
                 },
             }
@@ -36,7 +36,7 @@ class TestJavaApplication(TestApplicationJava):
         self.load('empty_war')
 
         assert 'success' in self.conf(
-            '"' + temp_dir + '/java/empty.war"',
+            f'"{temp_dir}/java/empty.war"',
             '/config/applications/empty_war/webapp',
         ), 'configure war'
 
@@ -118,7 +118,7 @@ class TestJavaApplication(TestApplicationJava):
         headers = self.get(
             headers={
                 'Host': 'localhost',
-                'Cookie': 'JSESSIONID=' + session_id,
+                'Cookie': f'JSESSIONID={session_id}',
                 'Connection': 'close',
             },
             url='/?var1=val2',
@@ -157,7 +157,7 @@ class TestJavaApplication(TestApplicationJava):
         resp = self.get(
             headers={
                 'Host': 'localhost',
-                'Cookie': 'JSESSIONID=' + session_id,
+                'Cookie': f'JSESSIONID={session_id}',
                 'Connection': 'close',
             }
         )
@@ -171,7 +171,7 @@ class TestJavaApplication(TestApplicationJava):
         resp = self.get(
             headers={
                 'Host': 'localhost',
-                'Cookie': 'JSESSIONID=' + session_id,
+                'Cookie': f'JSESSIONID={session_id}',
                 'Connection': 'close',
             }
         )
@@ -183,7 +183,7 @@ class TestJavaApplication(TestApplicationJava):
         resp = self.get(
             headers={
                 'Host': 'localhost',
-                'Cookie': 'JSESSIONID=' + session_id,
+                'Cookie': f'JSESSIONID={session_id}',
                 'Connection': 'close',
             }
         )
@@ -207,7 +207,7 @@ class TestJavaApplication(TestApplicationJava):
         resp = self.get(
             headers={
                 'Host': 'localhost',
-                'Cookie': 'JSESSIONID=' + session_id,
+                'Cookie': f'JSESSIONID={session_id}',
                 'Connection': 'close',
             }
         )
@@ -223,7 +223,7 @@ class TestJavaApplication(TestApplicationJava):
         resp = self.get(
             headers={
                 'Host': 'localhost',
-                'Cookie': 'JSESSIONID=' + session_id,
+                'Cookie': f'JSESSIONID={session_id}',
                 'Connection': 'close',
             }
         )
@@ -244,7 +244,7 @@ class TestJavaApplication(TestApplicationJava):
         headers = self.get(
             headers={
                 'Host': 'localhost',
-                'Cookie': 'JSESSIONID=' + session_id,
+                'Cookie': f'JSESSIONID={session_id}',
                 'Connection': 'close',
             },
             url='/?var1=val2',
@@ -256,7 +256,7 @@ class TestJavaApplication(TestApplicationJava):
         headers = self.get(
             headers={
                 'Host': 'localhost',
-                'Cookie': 'JSESSIONID=' + session_id,
+                'Cookie': f'JSESSIONID={session_id}',
                 'Connection': 'close',
             },
             url='/',
@@ -770,7 +770,7 @@ class TestJavaApplication(TestApplicationJava):
         assert headers['X-Path-Info'] == '/test', 'the rest of the path'
         assert (
             headers['X-Path-Translated']
-            == headers['X-Real-Path'] + headers['X-Path-Info']
+            == f"{headers['X-Real-Path']}{headers['X-Path-Info']}"
         ), 'translated path is the app root + path info'
         assert (
             headers['X-Resource-Paths'].endswith('/WEB-INF/, /index.html]')
@@ -956,7 +956,7 @@ class TestJavaApplication(TestApplicationJava):
         self.load('multipart')
 
         reldst = '/uploads'
-        fulldst = temp_dir + reldst
+        fulldst = f'{temp_dir}{reldst}'
         os.mkdir(fulldst)
         public_dir(fulldst)
 
@@ -989,7 +989,7 @@ class TestJavaApplication(TestApplicationJava):
         assert re.search(r'sample\.txt created', resp['body']), 'multipart body'
         assert (
             self.search_in_log(
-                r'^Data from sample file$', name=reldst + '/sample.txt'
+                r'^Data from sample file$', name=f'{reldst}/sample.txt'
             )
             is not None
         ), 'file created'

test/test_java_isolation_rootfs.py

@@ -13,17 +13,17 @@ class TestJavaIsolationRootfs(TestApplicationJava):
         if not is_su:
             pytest.skip('require root')
 
-        os.makedirs(option.temp_dir + '/jars')
-        os.makedirs(option.temp_dir + '/tmp')
-        os.chmod(option.temp_dir + '/tmp', 0o777)
+        os.makedirs(f'{option.temp_dir}/jars')
+        os.makedirs(f'{option.temp_dir}/tmp')
+        os.chmod(f'{option.temp_dir}/tmp', 0o777)
 
         try:
             subprocess.run(
                 [
                     "mount",
                     "--bind",
-                    option.current_dir + "/build",
-                    option.temp_dir + "/jars",
+                    f'{option.current_dir}/build',
+                    f'{option.temp_dir}/jars',
                 ],
                 stderr=subprocess.STDOUT,
             )
@@ -32,7 +32,7 @@ class TestJavaIsolationRootfs(TestApplicationJava):
             raise
 
         except subprocess.CalledProcessError:
-            pytest.fail('Can\'t run mount process.')
+            pytest.fail("Can't run mount process.")
 
     def teardown_method(self, is_su):
         if not is_su:
@@ -40,7 +40,7 @@ class TestJavaIsolationRootfs(TestApplicationJava):
 
         try:
             subprocess.run(
-                ["umount", "--lazy", option.temp_dir + "/jars"],
+                ["umount", "--lazy", f"{option.temp_dir}/jars"],
                 stderr=subprocess.STDOUT,
             )
 
@@ -48,7 +48,7 @@ class TestJavaIsolationRootfs(TestApplicationJava):
             raise
 
         except subprocess.CalledProcessError:
-            pytest.fail('Can\'t run umount process.')
+            pytest.fail("Can't run umount process.")
 
     def test_java_isolation_rootfs_chroot_war(self, is_su, temp_dir):
         if not is_su:

test/test_java_websockets.py

@@ -109,7 +109,7 @@ class TestJavaWebsockets(TestApplicationJava):
 
         frame = self.ws.frame_read(sock)
 
-        assert message + ' ' + message == frame['data'].decode(
+        assert f'{message} {message}' == frame['data'].decode(
             'utf-8'
         ), 'mirror framing'
 
@@ -454,21 +454,21 @@ class TestJavaWebsockets(TestApplicationJava):
         _, sock, _ = self.ws.upgrade()
 
         for i in range(0, 10):
-            self.ws.frame_write(sock, self.ws.OP_PING, 'payload-%d' % i)
+            self.ws.frame_write(sock, self.ws.OP_PING, f'payload-{i}')
 
         for i in range(0, 10):
             frame = self.ws.frame_read(sock)
-            self.check_frame(frame, True, self.ws.OP_PONG, 'payload-%d' % i)
+            self.check_frame(frame, True, self.ws.OP_PONG, f'payload-{i}')
 
         # 2_11
 
         for i in range(0, 10):
             opcode = self.ws.OP_PING
-            self.ws.frame_write(sock, opcode, 'payload-%d' % i, chopsize=1)
+            self.ws.frame_write(sock, opcode, f'payload-{i}', chopsize=1)
 
         for i in range(0, 10):
             frame = self.ws.frame_read(sock)
-            self.check_frame(frame, True, self.ws.OP_PONG, 'payload-%d' % i)
+            self.check_frame(frame, True, self.ws.OP_PONG, f'payload-{i}')
 
         self.close_connection(sock)
 

test/test_njs.py

@@ -13,13 +13,13 @@ class TestNJS(TestApplicationProto):
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
                 "routes": [
-                    {"action": {"share": option.temp_dir + "/assets$uri"}}
+                    {"action": {"share": f"{option.temp_dir}/assets$uri"}}
                 ],
             }
         )
 
     def create_files(self, *files):
-        assets_dir = option.temp_dir + '/assets/'
+        assets_dir = f'{option.temp_dir}/assets/'
         os.makedirs(assets_dir)
 
         [open(assets_dir + f, 'a') for f in files]
@@ -29,7 +29,7 @@ class TestNJS(TestApplicationProto):
         assert 'success' in self.conf(share, 'routes/0/action/share')
 
     def check_expression(self, expression, url='/'):
-        self.set_share('"`' + option.temp_dir + '/assets' + expression + '`"')
+        self.set_share(f'"`{option.temp_dir}/assets{expression}`"')
         assert self.get(url=url)['status'] == 200
 
     def test_njs_template_string(self, temp_dir):
@@ -39,7 +39,7 @@ class TestNJS(TestApplicationProto):
         self.check_expression('/\\\\`backtick')
         self.check_expression('/l1\\nl2')
 
-        self.set_share('"' + temp_dir + '/assets/`string`"')
+        self.set_share(f'"{temp_dir}/assets/`string`"')
         assert self.get()['status'] == 200
 
     def test_njs_template_expression(self, temp_dir):
@@ -63,7 +63,7 @@ class TestNJS(TestApplicationProto):
         self.check_expression('/${remoteAddr}')
         self.check_expression('/${headers.Host}')
 
-        self.set_share('"`' + temp_dir + '/assets/${cookies.foo}`"')
+        self.set_share(f'"`{temp_dir}/assets/${{cookies.foo}}`"')
         assert (
             self.get(headers={'Cookie': 'foo=str', 'Connection': 'close'})[
                 'status'
@@ -71,7 +71,7 @@ class TestNJS(TestApplicationProto):
             == 200
         ), 'cookies'
 
-        self.set_share('"`' + temp_dir + '/assets/${args.foo}`"')
+        self.set_share(f'"`{temp_dir}/assets/${{args.foo}}`"')
         assert self.get(url='/?foo=str')['status'] == 200, 'args'
 
     def test_njs_invalid(self, temp_dir, skip_alert):

test/test_node_application.py

@@ -146,7 +146,7 @@ class TestNodeApplication(TestApplicationNode):
         self.load('write_callback')
 
         assert self.get()['body'] == 'helloworld', 'write callback order'
-        assert waitforfiles(temp_dir + '/node/callback'), 'write callback'
+        assert waitforfiles(f'{temp_dir}/node/callback'), 'write callback'
 
     def test_node_application_write_before_write_head(self):
         self.load('write_before_write_head')
@@ -255,7 +255,7 @@ class TestNodeApplication(TestApplicationNode):
             )['status']
             == 200
         ), 'promise end request'
-        assert waitforfiles(temp_dir + '/node/callback'), 'promise end'
+        assert waitforfiles(f'{temp_dir}/node/callback'), 'promise end'
 
     @pytest.mark.skip('not yet')
     def test_node_application_header_name_valid(self):

test/test_node_websockets.py

@@ -109,7 +109,7 @@ class TestNodeWebsockets(TestApplicationNode):
 
         frame = self.ws.frame_read(sock)
 
-        assert message + ' ' + message == frame['data'].decode(
+        assert f'{message} {message}' == frame['data'].decode(
             'utf-8'
         ), 'mirror framing'
 
@@ -473,21 +473,21 @@ class TestNodeWebsockets(TestApplicationNode):
         _, sock, _ = self.ws.upgrade()
 
         for i in range(0, 10):
-            self.ws.frame_write(sock, self.ws.OP_PING, 'payload-%d' % i)
+            self.ws.frame_write(sock, self.ws.OP_PING, f'payload-{i}')
 
         for i in range(0, 10):
             frame = self.ws.frame_read(sock)
-            self.check_frame(frame, True, self.ws.OP_PONG, 'payload-%d' % i)
+            self.check_frame(frame, True, self.ws.OP_PONG, f'payload-{i}')
 
         # 2_11
 
         for i in range(0, 10):
             opcode = self.ws.OP_PING
-            self.ws.frame_write(sock, opcode, 'payload-%d' % i, chopsize=1)
+            self.ws.frame_write(sock, opcode, f'payload-{i}', chopsize=1)
 
         for i in range(0, 10):
             frame = self.ws.frame_read(sock)
-            self.check_frame(frame, True, self.ws.OP_PONG, 'payload-%d' % i)
+            self.check_frame(frame, True, self.ws.OP_PONG, f'payload-{i}')
 
         self.close_connection(sock)
 

test/test_php_application.py

@@ -33,28 +33,23 @@ class TestPHPApplication(TestApplicationPHP):
     def set_opcache(self, app, val):
         assert 'success' in self.conf(
             {"admin": {"opcache.enable": val, "opcache.enable_cli": val}},
-            'applications/' + app + '/options',
+            f'applications/{app}/options',
         )
 
         r = self.check_opcache()
         assert r['headers']['X-OPcache'] == val, 'opcache value'
 
     def set_preload(self, preload):
-        with open(option.temp_dir + '/php.ini', 'w') as f:
+        with open(f'{option.temp_dir}/php.ini', 'w') as f:
             f.write(
-                """opcache.preload = %(test_dir)s/php/opcache/preload\
-/%(preload)s
-opcache.preload_user = %(user)s
+                f"""opcache.preload = {option.test_dir}/php/opcache/preload\
+/{preload}
+opcache.preload_user = {option.user or getpass.getuser()}
 """
-                % {
-                    'test_dir': option.test_dir,
-                    'preload': preload,
-                    'user': option.user or getpass.getuser(),
-                }
             )
 
         assert 'success' in self.conf(
-            {"file": option.temp_dir + "/php.ini"},
+            {"file": f"{option.temp_dir}/php.ini"},
             'applications/opcache/options',
         )
 
@@ -295,7 +290,7 @@ opcache.preload_user = %(user)s
 
         assert (
             self.get()['headers']['X-File']
-            == option.test_dir + '/php/ini_precision/ini/php.ini'
+            == f'{option.test_dir}/php/ini_precision/ini/php.ini'
         ), 'ini file'
         assert self.get()['headers']['X-Precision'] == '4', 'ini value'
 
@@ -318,7 +313,7 @@ opcache.preload_user = %(user)s
 
         assert (
             self.get()['headers']['X-File']
-            == option.test_dir + '/php/ini_precision/ini/php.ini'
+            == f'{option.test_dir}/php/ini_precision/ini/php.ini'
         ), 'ini file'
         assert self.get()['headers']['X-Precision'] == '5', 'ini value admin'
 
@@ -332,7 +327,7 @@ opcache.preload_user = %(user)s
 
         assert (
             self.get()['headers']['X-File']
-            == option.test_dir + '/php/ini_precision/ini/php.ini'
+            == f'{option.test_dir}/php/ini_precision/ini/php.ini'
         ), 'ini file'
         assert self.get()['headers']['X-Precision'] == '5', 'ini value user'
 
@@ -590,7 +585,7 @@ opcache.preload_user = %(user)s
                     "script": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "root": option.test_dir + "/php/script",
+                        "root": f"{option.test_dir}/php/script",
                         "script": "phpinfo.php",
                     }
                 },
@@ -610,7 +605,7 @@ opcache.preload_user = %(user)s
                     "phpinfo": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "root": option.test_dir + "/php/phpinfo",
+                        "root": f"{option.test_dir}/php/phpinfo",
                     }
                 },
             }
@@ -622,18 +617,18 @@ opcache.preload_user = %(user)s
         assert resp['body'] != '', 'body not empty'
 
     def test_php_application_trailing_slash(self, temp_dir):
-        new_root = temp_dir + "/php-root"
-        os.makedirs(new_root + '/path')
+        new_root = f'{temp_dir}/php-root'
+        os.makedirs(f'{new_root}/path')
 
-        Path(new_root + '/path/index.php').write_text('<?php echo "OK\n"; ?>')
+        Path(f'{new_root}/path/index.php').write_text('<?php echo "OK\n"; ?>')
 
-        addr = temp_dir + '/sock'
+        addr = f'{temp_dir}/sock'
 
         assert 'success' in self.conf(
             {
                 "listeners": {
                     "*:7080": {"pass": "applications/php-path"},
-                    "unix:" + addr: {"pass": "applications/php-path"},
+                    f'unix:{addr}': {"pass": "applications/php-path"},
                 },
                 "applications": {
                     "php-path": {
@@ -665,9 +660,9 @@ opcache.preload_user = %(user)s
         ), 'Location with custom Host over UDS'
 
     def test_php_application_forbidden(self, temp_dir):
-        new_root = temp_dir + "/php-root"
-        os.makedirs(new_root + '/path')
-        os.chmod(new_root + '/path', 0o000)
+        new_root = f'{temp_dir}/php-root/path'
+        os.makedirs(new_root)
+        os.chmod(new_root, 0o000)
 
         assert 'success' in self.conf(
             {
@@ -676,7 +671,7 @@ opcache.preload_user = %(user)s
                     "php-path": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "root": new_root,
+                        "root": f'{temp_dir}/php-root',
                     }
                 },
             }
@@ -689,9 +684,9 @@ opcache.preload_user = %(user)s
 
         assert self.get(url='/index.wrong')['status'] != 200, 'status'
 
-        new_root = temp_dir + "/php"
+        new_root = f'{temp_dir}/php'
         os.mkdir(new_root)
-        shutil.copy(option.test_dir + '/php/phpinfo/index.wrong', new_root)
+        shutil.copy(f'{option.test_dir}/php/phpinfo/index.wrong', new_root)
 
         assert 'success' in self.conf(
             {
@@ -708,21 +703,21 @@ opcache.preload_user = %(user)s
         ), 'configure new root'
 
         resp = self.get()
-        assert str(resp['status']) + resp['body'] != '200', 'status new root'
+        assert f'{resp["status"]}{resp["body"]}' != '200', 'status new root'
 
     def run_php_application_cwd_root_tests(self):
         assert 'success' in self.conf_delete(
             'applications/cwd/working_directory'
         )
 
-        script_cwd = option.test_dir + '/php/cwd'
+        script_cwd = f'{option.test_dir}/php/cwd'
 
         resp = self.get()
         assert resp['status'] == 200, 'status ok'
         assert resp['body'] == script_cwd, 'default cwd'
 
         assert 'success' in self.conf(
-            '"' + option.test_dir + '"',
+            f'"{option.test_dir}"',
             'applications/cwd/working_directory',
         )
 
@@ -741,7 +736,7 @@ opcache.preload_user = %(user)s
         assert resp['body'] == script_cwd, 'cwd restored'
 
         resp = self.get(url='/subdir/')
-        assert resp['body'] == script_cwd + '/subdir', 'cwd subdir'
+        assert resp['body'] == f'{script_cwd}/subdir', 'cwd subdir'
 
     def test_php_application_cwd_root(self):
         self.load('cwd')
@@ -760,7 +755,7 @@ opcache.preload_user = %(user)s
     def run_php_application_cwd_script_tests(self):
         self.load('cwd')
 
-        script_cwd = option.test_dir + '/php/cwd'
+        script_cwd = f'{option.test_dir}/php/cwd'
 
         assert 'success' in self.conf_delete(
             'applications/cwd/working_directory'

test/test_php_targets.py

@@ -6,6 +6,7 @@ class TestPHPTargets(TestApplicationPHP):
     prerequisites = {'modules': {'php': 'any'}}
 
     def test_php_application_targets(self):
+        targets_dir = f"{option.test_dir}/php/targets"
         assert 'success' in self.conf(
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
@@ -27,15 +28,15 @@ class TestPHPTargets(TestApplicationPHP):
                         "targets": {
                             "1": {
                                 "script": "1.php",
-                                "root": option.test_dir + "/php/targets",
+                                "root": targets_dir,
                             },
                             "2": {
                                 "script": "2.php",
-                                "root": option.test_dir + "/php/targets/2",
+                                "root": f'{targets_dir}/2',
                             },
                             "default": {
                                 "index": "index.php",
-                                "root": option.test_dir + "/php/targets",
+                                "root": targets_dir,
                             },
                         },
                     }
@@ -72,7 +73,7 @@ class TestPHPTargets(TestApplicationPHP):
                         "targets": {
                             "default": {
                                 "index": "index.php",
-                                "root": option.test_dir + "/php/targets",
+                                "root": f"{option.test_dir}/php/targets",
                             },
                         },
                     }
@@ -85,7 +86,7 @@ class TestPHPTargets(TestApplicationPHP):
             {"pass": "applications/targets/blah"}, 'listeners/*:7080'
         ), 'invalid targets pass'
         assert 'error' in self.conf(
-            '"' + option.test_dir + '/php/targets\"',
+            f'"{option.test_dir}/php/targets"',
             'applications/targets/root',
         ), 'invalid root'
         assert 'error' in self.conf(

test/test_proxy.py

@@ -63,6 +63,7 @@ Content-Length: 10
         run_process(self.run_server, self.SERVER_PORT)
         waitforsocket(self.SERVER_PORT)
 
+        python_dir = f'{option.test_dir}/python'
         assert 'success' in self.conf(
             {
                 "listeners": {
@@ -74,24 +75,22 @@ Content-Length: 10
                     "mirror": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "path": option.test_dir + "/python/mirror",
-                        "working_directory": option.test_dir + "/python/mirror",
+                        "path": f'{python_dir}/mirror',
+                        "working_directory": f'{python_dir}/mirror',
                         "module": "wsgi",
                     },
                     "custom_header": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "path": option.test_dir + "/python/custom_header",
-                        "working_directory": option.test_dir
-                        + "/python/custom_header",
+                        "path": f'{python_dir}/custom_header',
+                        "working_directory": f'{python_dir}/custom_header',
                         "module": "wsgi",
                     },
                     "delayed": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "path": option.test_dir + "/python/delayed",
-                        "working_directory": option.test_dir
-                        + "/python/delayed",
+                        "path": f'{python_dir}/delayed',
+                        "working_directory": f'{python_dir}/delayed',
                         "module": "wsgi",
                     },
                 },
@@ -124,8 +123,8 @@ Content-Length: 10
                     "mirror": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "path": option.test_dir + "/python/mirror",
-                        "working_directory": option.test_dir + "/python/mirror",
+                        "path": f'{option.test_dir}/python/mirror',
+                        "working_directory": f'{option.test_dir}/python/mirror',
                         "module": "wsgi",
                     }
                 },
@@ -186,7 +185,7 @@ Content-Length: 10
         socks = []
         for i in range(10):
             sock = self.post_http10(
-                body=payload + str(i),
+                body=f'{payload}{i}',
                 no_recv=True,
                 read_buffer_size=buff_size,
             )
@@ -199,7 +198,7 @@ Content-Length: 10
             resp = self._resp_to_dict(resp)
 
             assert resp['status'] == 200, 'status'
-            assert resp['body'] == payload + str(i), 'body'
+            assert resp['body'] == f'{payload}{i}', 'body'
 
     def test_proxy_header(self):
         assert 'success' in self.conf(
@@ -214,7 +213,7 @@ Content-Length: 10
             == header_value
         ), 'custom header'
 
-        header_value = r'(),/:;<=>?@[\]{}\t !#$%&\'*+-.^_`|~'
+        header_value = r"(),/:;<=>?@[\]{}\t !#$%&'*+-.^_`|~"
         assert (
             self.get_http10(
                 headers={'Host': 'localhost', 'Custom-Header': header_value}
@@ -336,18 +335,18 @@ Content-Length: 10
         assert self.get_http10()['status'] == 200, 'status'
 
     def test_proxy_unix(self, temp_dir):
-        addr = temp_dir + '/sock'
+        addr = f'{temp_dir}/sock'
 
         assert 'success' in self.conf(
             {
                 "*:7080": {"pass": "routes"},
-                "unix:" + addr: {'application': 'mirror'},
+                f'unix:{addr}': {'application': 'mirror'},
             },
             'listeners',
         ), 'add unix listener configure'
 
         assert 'success' in self.conf(
-            [{"action": {"proxy": 'http://unix:' + addr}}], 'routes'
+            [{"action": {"proxy": f'http://unix:{addr}'}}], 'routes'
         ), 'proxy unix configure'
 
         assert self.get_http10()['status'] == 200, 'status'
@@ -420,13 +419,7 @@ Content-Length: 10
     @pytest.mark.skip('not yet')
     def test_proxy_content_length(self):
         assert 'success' in self.conf(
-            [
-                {
-                    "action": {
-                        "proxy": "http://127.0.0.1:" + str(self.SERVER_PORT)
-                    }
-                }
-            ],
+            [{"action": {"proxy": f'http://127.0.0.1:{self.SERVER_PORT}'}}],
             'routes',
         ), 'proxy backend configure'
 
@@ -484,8 +477,8 @@ Content-Length: 10
                     "mirror": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "path": option.test_dir + "/python/mirror",
-                        "working_directory": option.test_dir + "/python/mirror",
+                        "path": f'{option.test_dir}/python/mirror',
+                        "working_directory": f'{option.test_dir}/python/mirror',
                         "module": "wsgi",
                     },
                 },

test/test_proxy_chunked.py

@@ -61,7 +61,7 @@ class TestProxyChunked(TestApplicationPython):
                     else:
                         add = line
 
-                    req = req + add + '\r\n'
+                    req = f'{req}{add}\r\n'
 
             for chunk in re.split(r'([@#])', req):
                 if chunk == '@' or chunk == '#':
@@ -77,9 +77,9 @@ class TestProxyChunked(TestApplicationPython):
         body = '\r\n\r\n'
 
         for l, c in chunks:
-            body = body + l + '\r\n' + c + '\r\n'
+            body = f'{body}{l}\r\n{c}\r\n'
 
-        return body + '0\r\n\r\n'
+        return f'{body}0\r\n\r\n'
 
     def get_http10(self, *args, **kwargs):
         return self.get(*args, http_10=True, **kwargs)
@@ -96,7 +96,7 @@ class TestProxyChunked(TestApplicationPython):
                 "routes": [
                     {
                         "action": {
-                            "proxy": "http://127.0.0.1:" + str(self.SERVER_PORT)
+                            "proxy": f'http://127.0.0.1:{self.SERVER_PORT}'
                         }
                     }
                 ],
@@ -111,20 +111,20 @@ class TestProxyChunked(TestApplicationPython):
         part = '0123456789abcdef'
 
         assert (
-            self.get_http10(body=self.chunks([('1000', part + ' X 256')]))[
+            self.get_http10(body=self.chunks([('1000', f'{part} X 256')]))[
                 'body'
             ]
             == part * 256
         )
         assert (
-            self.get_http10(body=self.chunks([('100000', part + ' X 65536')]))[
+            self.get_http10(body=self.chunks([('100000', f'{part} X 65536')]))[
                 'body'
             ]
             == part * 65536
         )
         assert (
             self.get_http10(
-                body=self.chunks([('1000000', part + ' X 1048576')]),
+                body=self.chunks([('1000000', f'{part} X 1048576')]),
                 read_buffer_size=4096 * 4096,
             )['body']
             == part * 1048576
@@ -133,7 +133,7 @@ class TestProxyChunked(TestApplicationPython):
         assert (
             self.get_http10(
                 body=self.chunks(
-                    [('1000', part + ' X 256'), ('1000', part + ' X 256')]
+                    [('1000', f'{part} X 256'), ('1000', f'{part} X 256')]
                 )
             )['body']
             == part * 256 * 2
@@ -142,8 +142,8 @@ class TestProxyChunked(TestApplicationPython):
             self.get_http10(
                 body=self.chunks(
                     [
-                        ('100000', part + ' X 65536'),
-                        ('100000', part + ' X 65536'),
+                        ('100000', f'{part} X 65536'),
+                        ('100000', f'{part} X 65536'),
                     ]
                 )
             )['body']
@@ -153,8 +153,8 @@ class TestProxyChunked(TestApplicationPython):
             self.get_http10(
                 body=self.chunks(
                     [
-                        ('1000000', part + ' X 1048576'),
-                        ('1000000', part + ' X 1048576'),
+                        ('1000000', f'{part} X 1048576'),
+                        ('1000000', f'{part} X 1048576'),
                     ]
                 ),
                 read_buffer_size=4096 * 4096,

test/test_python_application.py

@@ -20,17 +20,16 @@ class TestPythonApplication(TestApplicationPython):
         body = 'Test body string.'
 
         resp = self.http(
-            b"""POST / HTTP/1.1
+            f"""POST / HTTP/1.1
 Host: localhost
-Content-Length: %d
+Content-Length: {len(body)}
 Custom-Header: blah
 Custom-hEader: Blah
 Content-Type: text/html
 Connection: close
 custom-header: BLAH
 
-%s"""
-            % (len(body), body.encode()),
+{body}""".encode(),
             raw=True,
         )
 
@@ -101,7 +100,7 @@ custom-header: BLAH
         self.load('prefix', prefix='/api/rest')
 
         def set_prefix(prefix):
-            self.conf('"' + prefix + '"', 'applications/prefix/prefix')
+            self.conf(f'"{prefix}"', 'applications/prefix/prefix')
 
         def check_prefix(url, script_name, path_info):
             resp = self.get(url=url)
@@ -585,12 +584,12 @@ last line: 987654321
         except version.InvalidVersion:
             pytest.skip('require python module version 3')
 
-        venv_path = temp_dir + '/venv'
+        venv_path = f'{temp_dir}/venv'
         venv.create(venv_path)
 
         self.load('unicode')
         assert 'success' in self.conf(
-            '"' + venv_path + '"',
+            f'"{venv_path}"',
             '/config/applications/unicode/home',
         )
         assert (
@@ -640,7 +639,7 @@ last line: 987654321
 
         assert self.wait_for_record(r'Traceback') is not None, 'traceback'
         assert (
-            self.wait_for_record(r'raise Exception\(\'first exception\'\)')
+            self.wait_for_record(r"raise Exception\('first exception'\)")
             is not None
         ), 'first exception raise'
         assert len(self.findall(r'Traceback')) == 1, 'traceback count 1'
@@ -659,7 +658,7 @@ last line: 987654321
         ), 'error 2'
 
         assert (
-            self.wait_for_record(r'raise Exception\(\'second exception\'\)')
+            self.wait_for_record(r"raise Exception\('second exception'\)")
             is not None
         ), 'exception raise second'
         assert len(self.findall(r'Traceback')) == 2, 'traceback count 2'
@@ -676,7 +675,7 @@ last line: 987654321
         )
 
         assert (
-            self.wait_for_record(r'raise Exception\(\'third exception\'\)')
+            self.wait_for_record(r"raise Exception\('third exception'\)")
             is not None
         ), 'exception raise third'
         assert len(self.findall(r'Traceback')) == 3, 'traceback count 3'
@@ -711,7 +710,7 @@ last line: 987654321
         )
 
         assert (
-            self.wait_for_record(r'raise Exception\(\'next exception\'\)')
+            self.wait_for_record(r"raise Exception\('next exception'\)")
             is not None
         ), 'exception raise next'
         assert len(self.findall(r'Traceback')) == 5, 'traceback count 5'
@@ -747,7 +746,7 @@ last line: 987654321
         ), 'error'
 
         assert (
-            self.wait_for_record(r'raise Exception\(\'close exception\'\)')
+            self.wait_for_record(r"raise Exception\('close exception'\)")
             is not None
         ), 'exception raise close'
         assert len(self.findall(r'Traceback')) == 8, 'traceback count 8'
@@ -781,18 +780,14 @@ last line: 987654321
         self.load('user_group', user='nobody', group=group)
 
         obj = self.getjson()['body']
-        assert obj['UID'] == nobody_uid, (
-            'nobody uid user=nobody group=%s' % group
-        )
-
-        assert obj['GID'] == group_id, 'nobody gid user=nobody group=%s' % group
+        assert obj['UID'] == nobody_uid, f'nobody uid user=nobody group={group}'
+        assert obj['GID'] == group_id, f'nobody gid user=nobody group={group}'
 
         self.load('user_group', group=group)
 
         obj = self.getjson()['body']
-        assert obj['UID'] == nobody_uid, 'nobody uid group=%s' % group
-
-        assert obj['GID'] == group_id, 'nobody gid group=%s' % group
+        assert obj['UID'] == nobody_uid, f'nobody uid group={group}'
+        assert obj['GID'] == group_id, f'nobody gid group={group}'
 
         self.load('user_group', user='root')
 

test/test_python_environment.py

@@ -38,7 +38,7 @@ class TestPythonEnvironment(TestApplicationPython):
                     'Connection': 'close',
                 }
             )['body']
-            == 'val1,'
+            == 'val1'
         ), 'set'
 
         self.conf({"var": "val2"}, 'applications/environment/environment')
@@ -51,7 +51,7 @@ class TestPythonEnvironment(TestApplicationPython):
                     'Connection': 'close',
                 }
             )['body']
-            == 'val2,'
+            == 'val2'
         ), 'update'
 
     def test_python_environment_replace(self):
@@ -67,7 +67,7 @@ class TestPythonEnvironment(TestApplicationPython):
                     'Connection': 'close',
                 }
             )['body']
-            == 'val1,'
+            == 'val1'
         ), 'set'
 
         self.conf({"var2": "val2"}, 'applications/environment/environment')
@@ -80,7 +80,7 @@ class TestPythonEnvironment(TestApplicationPython):
                     'Connection': 'close',
                 }
             )['body']
-            == 'val2,'
+            == 'val2'
         ), 'replace'
 
     def test_python_environment_clear(self):
@@ -99,7 +99,7 @@ class TestPythonEnvironment(TestApplicationPython):
                     'Connection': 'close',
                 }
             )['body']
-            == 'val1,val2,'
+            == 'val1,val2'
         ), 'set'
 
         self.conf({}, 'applications/environment/environment')
@@ -138,7 +138,7 @@ class TestPythonEnvironment(TestApplicationPython):
                     'Connection': 'close',
                 }
             )['body']
-            == '/,'
+            == '/'
         ), 'replace default'
 
         self.conf({}, 'applications/environment/environment')

test/test_python_isolation.py

@@ -20,13 +20,13 @@ class TestPythonIsolation(TestApplicationPython):
         ).decode()
 
         pid = re.search(
-            r'(\d+)\s*unit: "' + app_name + '" application', output
+            fr'(\d+)\s*unit: "{app_name}" application', output
         ).group(1)
 
-        cgroup = '/proc/' + pid + '/cgroup'
+        cgroup = f'/proc/{pid}/cgroup'
 
         if not os.path.isfile(cgroup):
-            pytest.skip('no cgroup at ' + cgroup)
+            pytest.skip(f'no cgroup at {cgroup}')
 
         with open(cgroup, 'r') as f:
             return f.read().rstrip()
@@ -59,7 +59,7 @@ class TestPythonIsolation(TestApplicationPython):
         self.load('ns_inspect', isolation=isolation)
 
         assert (
-            self.getjson(url='/?path=' + temp_dir)['body']['FileExists']
+            self.getjson(url=f'/?path={temp_dir}')['body']['FileExists']
             == False
         ), 'temp_dir does not exists in rootfs'
 
@@ -87,7 +87,7 @@ class TestPythonIsolation(TestApplicationPython):
         isolation = {'rootfs': temp_dir, 'automount': {'language_deps': False}}
         self.load('empty', isolation=isolation)
 
-        python_path = temp_dir + '/usr'
+        python_path = f'{temp_dir}/usr'
 
         assert findmnt().find(python_path) == -1
         assert self.get()['status'] != 200, 'disabled language_deps'
@@ -156,7 +156,7 @@ class TestPythonIsolation(TestApplicationPython):
             pytest.skip('cgroup is not supported')
 
         def set_two_cgroup_path(path, path2):
-            script_path = option.test_dir + '/python/empty'
+            script_path = f'{option.test_dir}/python/empty'
 
             assert 'success' in self.conf(
                 {
@@ -203,7 +203,7 @@ class TestPythonIsolation(TestApplicationPython):
             pytest.skip('cgroup is not supported')
 
         def check_invalid(path):
-            script_path = option.test_dir + '/python/empty'
+            script_path = f'{option.test_dir}/python/empty'
             assert 'error' in self.conf(
                 {
                     "listeners": {"*:7080": {"pass": "applications/empty"}},

test/test_python_isolation_chroot.py

@@ -16,7 +16,7 @@ class TestPythonIsolation(TestApplicationPython):
         self.load('ns_inspect', isolation=isolation)
 
         assert (
-            self.getjson(url='/?path=' + temp_dir)['body']['FileExists']
+            self.getjson(url=f'/?path={temp_dir}')['body']['FileExists']
             == False
         ), 'temp_dir does not exists in rootfs'
 

test/test_python_procman.py

@@ -12,8 +12,8 @@ class TestPythonProcman(TestApplicationPython):
     prerequisites = {'modules': {'python': 'any'}}
 
     def setup_method(self):
-        self.app_name = "app-" + option.temp_dir.split('/')[-1]
-        self.app_proc = 'applications/' + self.app_name + '/processes'
+        self.app_name = f'app-{option.temp_dir.split("/")[-1]}'
+        self.app_proc = f'applications/{self.app_name}/processes'
         self.load('empty', self.app_name)
 
     def pids_for_process(self):
@@ -23,7 +23,7 @@ class TestPythonProcman(TestApplicationPython):
 
         pids = set()
         for m in re.findall(
-            '.*unit: "' + self.app_name + '" application', output.decode()
+            fr'.*unit: "{self.app_name}" application', output.decode()
         ):
             pids.add(re.search(r'^\s*(\d+)', m).group(1))
 
@@ -126,7 +126,7 @@ class TestPythonProcman(TestApplicationPython):
         assert len(pids_new) == 3, 'reconf 3'
         assert pids.issubset(pids_new), 'reconf 3 only 1 new'
 
-        self.conf_proc('6', self.app_proc + '/spare')
+        self.conf_proc('6', f'{self.app_proc}/spare')
 
         pids = self.pids_for_process()
         assert len(pids) == 6, 'reconf 6'
@@ -176,10 +176,10 @@ class TestPythonProcman(TestApplicationPython):
     def test_python_processes_access(self):
         self.conf_proc('1')
 
-        path = '/' + self.app_proc
-        assert 'error' in self.conf_get(path + '/max')
-        assert 'error' in self.conf_get(path + '/spare')
-        assert 'error' in self.conf_get(path + '/idle_timeout')
+        path = f'/{self.app_proc}'
+        assert 'error' in self.conf_get(f'{path}/max')
+        assert 'error' in self.conf_get(f'{path}/spare')
+        assert 'error' in self.conf_get(f'{path}/idle_timeout')
 
     def test_python_processes_invalid(self):
         assert 'error' in self.conf(
@@ -206,7 +206,7 @@ class TestPythonProcman(TestApplicationPython):
 
     def test_python_restart(self, temp_dir):
         shutil.copyfile(
-            option.test_dir + '/python/restart/v1.py', temp_dir + '/wsgi.py'
+            f'{option.test_dir}/python/restart/v1.py', f'{temp_dir}/wsgi.py'
         )
 
         self.load(
@@ -220,14 +220,14 @@ class TestPythonProcman(TestApplicationPython):
         assert b == "v1", 'process started'
 
         shutil.copyfile(
-            option.test_dir + '/python/restart/v2.py', temp_dir + '/wsgi.py'
+            f'{option.test_dir}/python/restart/v2.py', f'{temp_dir}/wsgi.py'
         )
 
         b = self.get()['body']
         assert b == "v1", 'still old process'
 
         assert 'success' in self.conf_get(
-            '/control/applications/' + self.app_name + '/restart'
+            f'/control/applications/{self.app_name}/restart'
         ), 'restart processes'
 
         b = self.get()['body']
@@ -238,7 +238,7 @@ class TestPythonProcman(TestApplicationPython):
         ), 'application incorrect'
 
         assert 'error' in self.conf_delete(
-            '/control/applications/' + self.app_name + '/restart'
+            f'/control/applications/{self.app_name}/restart'
         ), 'method incorrect'
 
     def test_python_restart_multi(self):
@@ -248,7 +248,7 @@ class TestPythonProcman(TestApplicationPython):
         assert len(pids) == 2, 'restart 2 started'
 
         assert 'success' in self.conf_get(
-            '/control/applications/' + self.app_name + '/restart'
+            f'/control/applications/{self.app_name}/restart'
         ), 'restart processes'
 
         new_pids = self.pids_for_process()
@@ -272,7 +272,7 @@ class TestPythonProcman(TestApplicationPython):
         assert len(pids) == 2, 'longstarts == 2'
 
         assert 'success' in self.conf_get(
-            '/control/applications/' + self.app_name + '/restart'
+            f'/control/applications/{self.app_name}/restart'
         ), 'restart processes'
 
         # wait for longstarted app

test/test_python_targets.py

@@ -6,6 +6,8 @@ class TestPythonTargets(TestApplicationPython):
     prerequisites = {'modules': {'python': 'all'}}
 
     def test_python_targets(self):
+        python_dir = f'{option.test_dir}/python'
+
         assert 'success' in self.conf(
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
@@ -22,9 +24,8 @@ class TestPythonTargets(TestApplicationPython):
                 "applications": {
                     "targets": {
                         "type": self.get_application_type(),
-                        "working_directory": option.test_dir
-                        + "/python/targets/",
-                        "path": option.test_dir + '/python/targets/',
+                        "working_directory": f'{python_dir}/targets/',
+                        "path": f'{python_dir}/targets/',
                         "targets": {
                             "1": {
                                 "module": "wsgi",
@@ -49,6 +50,8 @@ class TestPythonTargets(TestApplicationPython):
         assert resp['body'] == '2'
 
     def test_python_targets_prefix(self):
+        python_dir = f'{option.test_dir}/python'
+
         assert 'success' in self.conf(
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
@@ -65,9 +68,8 @@ class TestPythonTargets(TestApplicationPython):
                 "applications": {
                     "targets": {
                         "type": "python",
-                        "working_directory": option.test_dir
-                        + "/python/targets/",
-                        "path": option.test_dir + '/python/targets/',
+                        "working_directory": f'{python_dir}/targets/',
+                        "path": f'{python_dir}/targets/',
                         "protocol": "wsgi",
                         "targets": {
                             "app": {

test/test_respawn.py

@@ -13,21 +13,21 @@ class TestRespawn(TestApplicationPython):
     PATTERN_CONTROLLER = 'unit: controller'
 
     def setup_method(self):
-        self.app_name = "app-" + option.temp_dir.split('/')[-1]
+        self.app_name = f'app-{option.temp_dir.split("/")[-1]}'
 
         self.load('empty', self.app_name)
 
         assert 'success' in self.conf(
-            '1', 'applications/' + self.app_name + '/processes'
+            '1', f'applications/{self.app_name}/processes'
         )
 
     def pid_by_name(self, name, ppid):
         output = subprocess.check_output(['ps', 'ax', '-O', 'ppid']).decode()
-        m = re.search(r'\s*(\d+)\s*' + str(ppid) + r'.*' + name, output)
+        m = re.search(fr'\s*(\d+)\s*{ppid}.*{name}', output)
         return None if m is None else m.group(1)
 
     def kill_pids(self, *pids):
-        subprocess.call(['kill', '-9'] + list(pids))
+        subprocess.call(['kill', '-9', *pids])
 
     def wait_for_process(self, process, unit_pid):
         for i in range(50):
@@ -41,11 +41,11 @@ class TestRespawn(TestApplicationPython):
         return found
 
     def find_proc(self, name, ppid, ps_output):
-        return re.findall(str(ppid) + r'.*' + name, ps_output)
+        return re.findall(fr'{ppid}.*{name}', ps_output)
 
     def smoke_test(self, unit_pid):
         for _ in range(10):
-            r = self.conf('1', 'applications/' + self.app_name + '/processes')
+            r = self.conf('1', f'applications/{self.app_name}/processes')
 
             if 'success' in r:
                 break
@@ -68,7 +68,7 @@ class TestRespawn(TestApplicationPython):
         pid = self.pid_by_name(self.PATTERN_ROUTER, unit_pid)
 
         self.kill_pids(pid)
-        skip_alert(r'process %s exited on signal 9' % pid)
+        skip_alert(fr'process {pid} exited on signal 9')
 
         assert self.wait_for_process(self.PATTERN_ROUTER, unit_pid) is not None
 
@@ -79,7 +79,7 @@ class TestRespawn(TestApplicationPython):
         pid = self.pid_by_name(self.PATTERN_CONTROLLER, unit_pid)
 
         self.kill_pids(pid)
-        skip_alert(r'process %s exited on signal 9' % pid)
+        skip_alert(fr'process {pid} exited on signal 9')
 
         assert (
             self.wait_for_process(self.PATTERN_CONTROLLER, unit_pid) is not None
@@ -93,7 +93,7 @@ class TestRespawn(TestApplicationPython):
         pid = self.pid_by_name(self.app_name, unit_pid)
 
         self.kill_pids(pid)
-        skip_alert(r'process %s exited on signal 9' % pid)
+        skip_alert(fr'process {pid} exited on signal 9')
 
         assert self.wait_for_process(self.app_name, unit_pid) is not None
 

test/test_return.py

@@ -107,26 +107,26 @@ Connection: close
         check_location(reserved)
 
         # After first "?" all other "?" encoded.
-        check_location("/?" + reserved, "/?:/%3F#[]@!&'()*+,;=")
+        check_location(f'/?{reserved}', "/?:/%3F#[]@!&'()*+,;=")
         check_location("???", "?%3F%3F")
 
         # After first "#" all other "?" or "#" encoded.
-        check_location("/#" + reserved, "/#:/%3F%23[]@!&'()*+,;=")
+        check_location(f'/#{reserved}', "/#:/%3F%23[]@!&'()*+,;=")
         check_location("##?#?", "#%23%3F%23%3F")
 
         # After first "?" next "#" not encoded.
-        check_location("/?#" + reserved, "/?#:/%3F%23[]@!&'()*+,;=")
+        check_location(f'/?#{reserved}', "/?#:/%3F%23[]@!&'()*+,;=")
         check_location("??##", "?%3F#%23")
         check_location("/?##?", "/?#%23%3F")
 
         # Unreserved never encoded.
         check_location(unreserved)
-        check_location("/" + unreserved + "?" + unreserved + "#" + unreserved)
+        check_location(f'/{unreserved}?{unreserved}#{unreserved}')
 
         # Unsafe always encoded.
         check_location(unsafe, unsafe_enc)
-        check_location("?" + unsafe, "?" + unsafe_enc)
-        check_location("#" + unsafe, "#" + unsafe_enc)
+        check_location(f'?{unsafe}', f'?{unsafe_enc}')
+        check_location(f'#{unsafe}', f'#{unsafe_enc}')
 
         # %00-%20 and %7F-%FF always encoded.
         check_location(u"\u0000\u0018\u001F\u0020\u0021", "%00%18%1F%20!")

test/test_routing.py

@@ -286,17 +286,18 @@ class TestRouting(TestApplicationPython):
         assert self.get(url='/BLAH')['status'] == 200, '/BLAH'
 
     def test_routes_pass_encode(self):
+        python_dir = f'{option.test_dir}/python'
+
         def check_pass(path, name):
             assert 'success' in self.conf(
                 {
-                    "listeners": {"*:7080": {"pass": "applications/" + path}},
+                    "listeners": {"*:7080": {"pass": f'applications/{path}'}},
                     "applications": {
                         name: {
                             "type": self.get_application_type(),
                             "processes": {"spare": 0},
-                            "path": option.test_dir + '/python/empty',
-                            "working_directory": option.test_dir
-                            + '/python/empty',
+                            "path": f'{python_dir}/empty',
+                            "working_directory": f'{python_dir}/empty',
                             "module": "wsgi",
                         }
                     },
@@ -313,14 +314,13 @@ class TestRouting(TestApplicationPython):
         def check_pass_error(path, name):
             assert 'error' in self.conf(
                 {
-                    "listeners": {"*:7080": {"pass": "applications/" + path}},
+                    "listeners": {"*:7080": {"pass": f'applications/{path}'}},
                     "applications": {
                         name: {
                             "type": self.get_application_type(),
                             "processes": {"spare": 0},
-                            "path": option.test_dir + '/python/empty',
-                            "working_directory": option.test_dir
-                            + '/python/empty',
+                            "path": f'{python_dir}/empty',
+                            "working_directory": f'{python_dir}/empty',
                             "module": "wsgi",
                         }
                     },
@@ -338,8 +338,8 @@ class TestRouting(TestApplicationPython):
                     "empty": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "path": option.test_dir + '/python/empty',
-                        "working_directory": option.test_dir + '/python/empty',
+                        "path": f'{option.test_dir}/python/empty',
+                        "working_directory": f'{option.test_dir}/python/empty',
                         "module": "wsgi",
                     }
                 },
@@ -1109,21 +1109,21 @@ class TestRouting(TestApplicationPython):
                 "E",
                 "F",
             ]:
-                chars_enc += "%" + h1 + h2
+                chars_enc += f'%{h1}{h2}'
         chars_enc = chars_enc[:-3]
 
         def check_args(args, query):
             self.route_match({"arguments": args})
-            assert self.get(url='/?' + query)['status'] == 200
+            assert self.get(url=f'/?{query}')['status'] == 200
 
-        check_args({chars: chars}, chars + '=' + chars)
-        check_args({chars: chars}, chars + '=' + chars_enc)
-        check_args({chars: chars}, chars_enc + '=' + chars)
-        check_args({chars: chars}, chars_enc + '=' + chars_enc)
-        check_args({chars_enc: chars_enc}, chars + '=' + chars)
-        check_args({chars_enc: chars_enc}, chars + '=' + chars_enc)
-        check_args({chars_enc: chars_enc}, chars_enc + '=' + chars)
-        check_args({chars_enc: chars_enc}, chars_enc + '=' + chars_enc)
+        check_args({chars: chars}, f'{chars}={chars}')
+        check_args({chars: chars}, f'{chars}={chars_enc}')
+        check_args({chars: chars}, f'{chars_enc}={chars}')
+        check_args({chars: chars}, f'{chars_enc}={chars_enc}')
+        check_args({chars_enc: chars_enc}, f'{chars}={chars}')
+        check_args({chars_enc: chars_enc}, f'{chars}={chars_enc}')
+        check_args({chars_enc: chars_enc}, f'{chars_enc}={chars}')
+        check_args({chars_enc: chars_enc}, f'{chars_enc}={chars_enc}')
 
     def test_routes_match_arguments_empty(self):
         self.route_match({"arguments": {}})
@@ -1492,28 +1492,28 @@ class TestRouting(TestApplicationPython):
         sock, port = sock_port()
         sock2, port2 = sock_port()
 
-        self.route_match({"source": "127.0.0.1:" + str(port)})
+        self.route_match({"source": f'127.0.0.1:{port}'})
         assert self.get(sock=sock)['status'] == 200, 'exact'
         assert self.get(sock=sock2)['status'] == 404, 'exact 2'
 
         sock, port = sock_port()
         sock2, port2 = sock_port()
 
-        self.route_match({"source": "!127.0.0.1:" + str(port)})
+        self.route_match({"source": f'!127.0.0.1:{port}'})
         assert self.get(sock=sock)['status'] == 404, 'negative'
         assert self.get(sock=sock2)['status'] == 200, 'negative 2'
 
         sock, port = sock_port()
         sock2, port2 = sock_port()
 
-        self.route_match({"source": ["*:" + str(port), "!127.0.0.1"]})
+        self.route_match({"source": [f'*:{port}', "!127.0.0.1"]})
         assert self.get(sock=sock)['status'] == 404, 'negative 3'
         assert self.get(sock=sock2)['status'] == 404, 'negative 4'
 
         sock, port = sock_port()
         sock2, port2 = sock_port()
 
-        self.route_match({"source": "127.0.0.1:" + str(port) + "-" + str(port)})
+        self.route_match({"source": f'127.0.0.1:{port}-{port}'})
         assert self.get(sock=sock)['status'] == 200, 'range single'
         assert self.get(sock=sock2)['status'] == 404, 'range single 2'
 
@@ -1526,14 +1526,7 @@ class TestRouting(TestApplicationPython):
         ]
         socks.sort(key=lambda sock: sock[1])
 
-        self.route_match(
-            {
-                "source": "127.0.0.1:"
-                + str(socks[1][1])  # second port number
-                + "-"
-                + str(socks[3][1])  # fourth port number
-            }
-        )
+        self.route_match({"source": f'127.0.0.1:{socks[1][1]}-{socks[3][1]}'})
         assert self.get(sock=socks[0][0])['status'] == 404, 'range'
         assert self.get(sock=socks[1][0])['status'] == 200, 'range 2'
         assert self.get(sock=socks[2][0])['status'] == 200, 'range 3'
@@ -1550,8 +1543,8 @@ class TestRouting(TestApplicationPython):
         self.route_match(
             {
                 "source": [
-                    "127.0.0.1:" + str(socks[0][1]),
-                    "127.0.0.1:" + str(socks[2][1]),
+                    f'127.0.0.1:{socks[0][1]}',
+                    f'127.0.0.1:{socks[2][1]}',
                 ]
             }
         )
@@ -1734,12 +1727,12 @@ class TestRouting(TestApplicationPython):
         assert self.get(port=7081)['status'] == 404, '0 ipv4'
 
     def test_routes_source_unix(self, temp_dir):
-        addr = temp_dir + '/sock'
+        addr = f'{temp_dir}/sock'
 
         assert 'success' in self.conf(
             {
                 "127.0.0.1:7081": {"pass": "routes"},
-                "unix:" + addr: {"pass": "routes"},
+                f'unix:{addr}': {"pass": "routes"},
             },
             'listeners',
         ), 'source listeners configure'

test/test_ruby_hooks.py

@@ -8,7 +8,7 @@ class TestRubyHooks(TestApplicationRuby):
 
     def _wait_cookie(self, pattern, count):
         return waitforglob(
-            option.temp_dir + '/ruby/hooks/cookie_' + pattern, count
+            f'{option.temp_dir}/ruby/hooks/cookie_{pattern}', count
         )
 
     def test_ruby_hooks_eval(self):

test/test_settings.py

@@ -44,7 +44,7 @@ class TestSettings(TestApplicationPython):
             headers = {'Host': 'localhost', 'Connection': 'close'}
 
             for i in range(headers_num):
-                headers['Custom-header-' + str(i)] = 'a' * 8000
+                headers[f'Custom-header-{i}'] = 'a' * 8000
 
             assert self.get(headers=headers)['status'] == expect
 
@@ -229,15 +229,12 @@ Connection: close
             sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
             sock.connect(addr)
 
-            req = (
-                """GET / HTTP/1.1
+            req = f"""GET / HTTP/1.1
 Host: localhost
-X-Length: %d
+X-Length: {data_len}
 Connection: close
 
 """
-                % data_len
-            )
 
             sock.sendall(req.encode())
 
@@ -259,10 +256,10 @@ Connection: close
 
         data_len = 1048576 if len(values) == 0 else 10 * max(values)
 
-        addr = temp_dir + '/sock'
+        addr = f'{temp_dir}/sock'
 
         assert 'success' in self.conf(
-            {"unix:" + addr: {'application': 'body_generate'}}, 'listeners'
+            {f'unix:{addr}': {'application': 'body_generate'}}, 'listeners'
         )
 
         assert 'success' in self.conf({'http': {'send_timeout': 1}}, 'settings')

test/test_static.py

@@ -11,13 +11,13 @@ class TestStatic(TestApplicationProto):
     prerequisites = {}
 
     def setup_method(self):
-        os.makedirs(option.temp_dir + '/assets/dir')
-        with open(option.temp_dir + '/assets/index.html', 'w') as index, open(
-            option.temp_dir + '/assets/README', 'w'
+        os.makedirs(f'{option.temp_dir}/assets/dir')
+        with open(f'{option.temp_dir}/assets/index.html', 'w') as index, open(
+            f'{option.temp_dir}/assets/README', 'w'
         ) as readme, open(
-            option.temp_dir + '/assets/log.log', 'w'
+            f'{option.temp_dir}/assets/log.log', 'w'
         ) as log, open(
-            option.temp_dir + '/assets/dir/file', 'w'
+            f'{option.temp_dir}/assets/dir/file', 'w'
         ) as file:
             index.write('0123456789')
             readme.write('readme')
@@ -28,7 +28,7 @@ class TestStatic(TestApplicationProto):
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
                 "routes": [
-                    {"action": {"share": option.temp_dir + "/assets$uri"}}
+                    {"action": {"share": f'{option.temp_dir}/assets$uri'}}
                 ],
                 "settings": {
                     "http": {
@@ -40,10 +40,10 @@ class TestStatic(TestApplicationProto):
             }
         )
 
-    def test_static_index(self):
+    def test_static_index(self, temp_dir):
         def set_index(index):
             assert 'success' in self.conf(
-                {"share": option.temp_dir + "/assets$uri", "index": index},
+                {"share": f'{temp_dir}/assets$uri', "index": index},
                 'routes/0/action',
             ), 'configure index'
 
@@ -72,12 +72,12 @@ class TestStatic(TestApplicationProto):
             resp['headers']['Content-Type'] == 'text/html'
         ), 'index not found 2 Content-Type'
 
-    def test_static_index_invalid(self, skip_alert):
+    def test_static_index_invalid(self, skip_alert, temp_dir):
         skip_alert(r'failed to apply new conf')
 
         def check_index(index):
             assert 'error' in self.conf(
-                {"share": option.temp_dir + "/assets$uri", "index": index},
+                {"share": f'{temp_dir}/assets$uri', "index": index},
                 'routes/0/action',
             )
 
@@ -86,7 +86,7 @@ class TestStatic(TestApplicationProto):
 
     def test_static_large_file(self, temp_dir):
         file_size = 32 * 1024 * 1024
-        with open(temp_dir + '/assets/large', 'wb') as f:
+        with open(f'{temp_dir}/assets/large', 'wb') as f:
             f.seek(file_size - 1)
             f.write(b'\0')
 
@@ -102,7 +102,7 @@ class TestStatic(TestApplicationProto):
         assert etag != etag_2, 'different ETag'
         assert etag == self.get(url='/')['headers']['ETag'], 'same ETag'
 
-        with open(temp_dir + '/assets/index.html', 'w') as f:
+        with open(f'{temp_dir}/assets/index.html', 'w') as f:
             f.write('blah')
 
         assert etag != self.get(url='/')['headers']['ETag'], 'new ETag'
@@ -114,19 +114,21 @@ class TestStatic(TestApplicationProto):
         assert 'Content-Type' not in resp['headers'], 'redirect Content-Type'
 
     def test_static_space_in_name(self, temp_dir):
+        assets_dir = f'{temp_dir}/assets'
+
         os.rename(
-            temp_dir + '/assets/dir/file',
-            temp_dir + '/assets/dir/fi le',
+            f'{assets_dir}/dir/file',
+            f'{assets_dir}/dir/fi le',
         )
-        assert waitforfiles(temp_dir + '/assets/dir/fi le')
+        assert waitforfiles(f'{assets_dir}/dir/fi le')
         assert self.get(url='/dir/fi le')['body'] == 'blah', 'file name'
 
-        os.rename(temp_dir + '/assets/dir', temp_dir + '/assets/di r')
-        assert waitforfiles(temp_dir + '/assets/di r/fi le')
+        os.rename(f'{assets_dir}/dir', f'{assets_dir}/di r')
+        assert waitforfiles(f'{assets_dir}/di r/fi le')
         assert self.get(url='/di r/fi le')['body'] == 'blah', 'dir name'
 
-        os.rename(temp_dir + '/assets/di r', temp_dir + '/assets/ di r ')
-        assert waitforfiles(temp_dir + '/assets/ di r /fi le')
+        os.rename(f'{assets_dir}/di r', f'{assets_dir}/ di r ')
+        assert waitforfiles(f'{assets_dir}/ di r /fi le')
         assert (
             self.get(url='/ di r /fi le')['body'] == 'blah'
         ), 'dir name enclosing'
@@ -147,16 +149,16 @@ class TestStatic(TestApplicationProto):
         ), 'encoded 2'
 
         os.rename(
-            temp_dir + '/assets/ di r /fi le',
-            temp_dir + '/assets/ di r / fi le ',
+            f'{assets_dir}/ di r /fi le',
+            f'{assets_dir}/ di r / fi le ',
         )
-        assert waitforfiles(temp_dir + '/assets/ di r / fi le ')
+        assert waitforfiles(f'{assets_dir}/ di r / fi le ')
         assert (
             self.get(url='/%20di%20r%20/%20fi%20le%20')['body'] == 'blah'
         ), 'file name enclosing'
 
         try:
-            open(temp_dir + '/ф а', 'a').close()
+            open(f'{temp_dir}/ф а', 'a').close()
             utf8 = True
 
         except KeyboardInterrupt:
@@ -167,33 +169,33 @@ class TestStatic(TestApplicationProto):
 
         if utf8:
             os.rename(
-                temp_dir + '/assets/ di r / fi le ',
-                temp_dir + '/assets/ di r /фа йл',
+                f'{assets_dir}/ di r / fi le ',
+                f'{assets_dir}/ di r /фа йл',
             )
-            assert waitforfiles(temp_dir + '/assets/ di r /фа йл')
+            assert waitforfiles(f'{assets_dir}/ di r /фа йл')
             assert (
                 self.get(url='/ di r /фа йл')['body'] == 'blah'
             ), 'file name 2'
 
             os.rename(
-                temp_dir + '/assets/ di r ',
-                temp_dir + '/assets/ди ректория',
+                f'{assets_dir}/ di r ',
+                f'{assets_dir}/ди ректория',
             )
-            assert waitforfiles(temp_dir + '/assets/ди ректория/фа йл')
+            assert waitforfiles(f'{assets_dir}/ди ректория/фа йл')
             assert (
                 self.get(url='/ди ректория/фа йл')['body'] == 'blah'
             ), 'dir name 2'
 
     def test_static_unix_socket(self, temp_dir):
         sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
-        sock.bind(temp_dir + '/assets/unix_socket')
+        sock.bind(f'{temp_dir}/assets/unix_socket')
 
         assert self.get(url='/unix_socket')['status'] == 404, 'socket'
 
         sock.close()
 
     def test_static_unix_fifo(self, temp_dir):
-        os.mkfifo(temp_dir + '/assets/fifo')
+        os.mkfifo(f'{temp_dir}/assets/fifo')
 
         assert self.get(url='/fifo')['status'] == 404, 'fifo'
 
@@ -346,5 +348,5 @@ Content-Length: 6\r
             raw_resp=True,
             raw=True,
             sock_type='unix',
-            addr=temp_dir + '/control.unit.sock',
+            addr=f'{temp_dir}/control.unit.sock',
         ), 'mime_types invalid'

test/test_static_chroot.py

@@ -3,6 +3,7 @@ from pathlib import Path
 
 import pytest
 from unit.applications.proto import TestApplicationProto
+from unit.option import option
 
 
 class TestStaticChroot(TestApplicationProto):
@@ -10,22 +11,22 @@ class TestStaticChroot(TestApplicationProto):
 
     @pytest.fixture(autouse=True)
     def setup_method_fixture(self, temp_dir):
-        os.makedirs(temp_dir + '/assets/dir')
-        Path(temp_dir + '/assets/index.html').write_text('0123456789')
-        Path(temp_dir + '/assets/dir/file').write_text('blah')
+        os.makedirs(f'{temp_dir}/assets/dir')
+        Path(f'{temp_dir}/assets/index.html').write_text('0123456789')
+        Path(f'{temp_dir}/assets/dir/file').write_text('blah')
 
-        self.test_path = '/' + os.path.relpath(Path(__file__))
+        self.test_path = f'/{os.path.relpath(Path(__file__))}'
 
         self._load_conf(
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
-                "routes": [{"action": {"share": temp_dir + "/assets$uri"}}],
+                "routes": [{"action": {"share": f'{temp_dir}/assets$uri'}}],
             }
         )
 
-    def update_action(self, share, chroot):
+    def update_action(self, chroot, share=f'{option.temp_dir}/assets$uri'):
         return self.conf(
-            {"share": share, "chroot": chroot},
+            {'chroot': chroot, 'share': share},
             'routes/0/action',
         )
 
@@ -38,9 +39,7 @@ class TestStaticChroot(TestApplicationProto):
         assert self.get(url='/dir/file')['status'] == 200, 'default chroot'
         assert self.get(url='/index.html')['status'] == 200, 'default chroot 2'
 
-        assert 'success' in self.update_action(
-            temp_dir + "/assets$uri", temp_dir + "/assets/dir"
-        )
+        assert 'success' in self.update_action(f'{temp_dir}/assets/dir')
 
         assert self.get(url='/dir/file')['status'] == 200, 'chroot'
         assert self.get(url='/index.html')['status'] == 403, 'chroot 403 2'
@@ -48,101 +47,89 @@ class TestStaticChroot(TestApplicationProto):
 
     def test_share_chroot_array(self, temp_dir):
         assert 'success' in self.update_action(
-            ["/blah", temp_dir + "/assets$uri"], temp_dir + "/assets/dir"
+            f'{temp_dir}/assets/dir', ["/blah", f'{temp_dir}/assets$uri']
         )
         assert self.get(url='/dir/file')['status'] == 200, 'share array'
 
         assert 'success' in self.update_action(
-            ["/blah", temp_dir + '/assets$uri'], temp_dir + '/assets/$host'
+            f'{temp_dir}/assets/$host',
+            ['/blah', f'{temp_dir}/assets$uri'],
         )
         assert self.get_custom('/dir/file', 'dir') == 200, 'array variable'
 
         assert 'success' in self.update_action(
-            ["/blah", "/blah2"], temp_dir + "/assets/dir"
+            f'{temp_dir}/assets/dir', ['/blah', '/blah2']
         )
         assert self.get()['status'] != 200, 'share array bad'
 
     def test_static_chroot_permission(self, is_su, temp_dir):
         if is_su:
-            pytest.skip('does\'t work under root')
+            pytest.skip("does't work under root")
 
-        os.chmod(temp_dir + '/assets/dir', 0o100)
+        os.chmod(f'{temp_dir}/assets/dir', 0o100)
 
         assert 'success' in self.update_action(
-            temp_dir + "/assets$uri", temp_dir + "/assets/dir"
+            f'{temp_dir}/assets/dir'
         ), 'configure chroot'
 
         assert self.get(url='/dir/file')['status'] == 200, 'chroot'
 
     def test_static_chroot_empty(self, temp_dir):
-        assert 'success' in self.update_action(temp_dir + "/assets$uri", "")
+        assert 'success' in self.update_action('')
         assert self.get(url='/dir/file')['status'] == 200, 'empty absolute'
 
-        assert 'success' in self.update_action(".$uri", "")
+        assert 'success' in self.update_action("", ".$uri")
         assert self.get(url=self.test_path)['status'] == 200, 'empty relative'
 
     def test_static_chroot_relative(self, is_su, temp_dir):
         if is_su:
-            pytest.skip('does\'t work under root')
+            pytest.skip("Does't work under root.")
 
-        assert 'success' in self.update_action(temp_dir + "/assets$uri", ".")
+        assert 'success' in self.update_action('.')
         assert self.get(url='/dir/file')['status'] == 403, 'relative chroot'
 
         assert 'success' in self.conf({"share": ".$uri"}, 'routes/0/action')
         assert self.get(url=self.test_path)['status'] == 200, 'relative share'
 
-        assert 'success' in self.update_action(".$uri", ".")
+        assert 'success' in self.update_action(".", ".$uri")
         assert self.get(url=self.test_path)['status'] == 200, 'relative'
 
     def test_static_chroot_variables(self, temp_dir):
-        assert 'success' in self.update_action(
-            temp_dir + '/assets$uri', temp_dir + '/assets/$host'
-        )
+        assert 'success' in self.update_action(f'{temp_dir}/assets/$host')
         assert self.get_custom('/dir/file', 'dir') == 200
 
-        assert 'success' in self.update_action(
-            temp_dir + '/assets$uri', temp_dir + '/assets/${host}'
-        )
+        assert 'success' in self.update_action(f'{temp_dir}/assets/${{host}}')
         assert self.get_custom('/dir/file', 'dir') == 200
 
     def test_static_chroot_variables_buildin_start(self, temp_dir):
         assert 'success' in self.update_action(
-            temp_dir + '/assets/dir/$host', '$uri/assets/dir'
+            '$uri/assets/dir',
+            f'{temp_dir}/assets/dir/$host',
         )
         assert self.get_custom(temp_dir, 'file') == 200
 
     def test_static_chroot_variables_buildin_mid(self, temp_dir):
-        assert 'success' in self.update_action(
-            temp_dir + '/assets$uri', temp_dir + '/$host/dir'
-        )
+        assert 'success' in self.update_action(f'{temp_dir}/$host/dir')
         assert self.get_custom('/dir/file', 'assets') == 200
 
     def test_static_chroot_variables_buildin_end(self, temp_dir):
-        assert 'success' in self.update_action(
-            temp_dir + '/assets$uri', temp_dir + '/assets/$host'
-        )
+        assert 'success' in self.update_action(f'{temp_dir}/assets/$host')
         assert self.get_custom('/dir/file', 'dir') == 200
 
     def test_static_chroot_slash(self, temp_dir):
-        assert 'success' in self.update_action(
-            temp_dir + "/assets$uri", temp_dir + "/assets/dir/"
-        )
+        assert 'success' in self.update_action(f'{temp_dir}/assets/dir/')
         assert self.get(url='/dir/file')['status'] == 200, 'slash end'
         assert self.get(url='/dirxfile')['status'] == 403, 'slash end bad'
 
-        assert 'success' in self.update_action(
-            temp_dir + "/assets$uri", temp_dir + "/assets/dir"
-        )
+        assert 'success' in self.update_action(f'{temp_dir}/assets/dir')
         assert self.get(url='/dir/file')['status'] == 200, 'no slash end'
 
-        assert 'success' in self.update_action(
-            temp_dir + "/assets$uri", temp_dir + "/assets/dir/"
-        )
+        assert 'success' in self.update_action(f'{temp_dir}/assets/dir/')
         assert self.get(url='/dir/file')['status'] == 200, 'slash end 2'
         assert self.get(url='/dirxfile')['status'] == 403, 'slash end 2 bad'
 
         assert 'success' in self.update_action(
-            temp_dir + "///assets/////$uri", temp_dir + "//assets////dir///"
+            f'{temp_dir}//assets////dir///', f'{temp_dir}///assets/////$uri'
         )
         assert self.get(url='/dir/file')['status'] == 200, 'multiple slashes'
 
@@ -160,9 +147,5 @@ class TestStaticChroot(TestApplicationProto):
             'routes/0/action',
         ), 'configure mount error'
 
-        assert 'error' in self.update_action(
-            temp_dir + '/assets$uri', temp_dir + '/assets/d$r$uri'
-        )
-        assert 'error' in self.update_action(
-            temp_dir + '/assets$uri', temp_dir + '/assets/$$uri'
-        )
+        assert 'error' in self.update_action(f'{temp_dir}/assets/d$r$uri')
+        assert 'error' in self.update_action(f'{temp_dir}/assets/$$uri')

test/test_static_fallback.py

@@ -10,11 +10,12 @@ class TestStaticFallback(TestApplicationProto):
 
     @pytest.fixture(autouse=True)
     def setup_method_fixture(self, temp_dir):
-        os.makedirs(temp_dir + '/assets/dir')
-        Path(temp_dir + '/assets/index.html').write_text('0123456789')
+        assets_dir = f'{temp_dir}/assets'
+        os.makedirs(f'{assets_dir}/dir')
+        Path(f'{assets_dir}/index.html').write_text('0123456789')
 
-        os.makedirs(temp_dir + '/assets/403')
-        os.chmod(temp_dir + '/assets/403', 0o000)
+        os.makedirs(f'{assets_dir}/403')
+        os.chmod(f'{assets_dir}/403', 0o000)
 
         self._load_conf(
             {
@@ -22,7 +23,7 @@ class TestStaticFallback(TestApplicationProto):
                     "*:7080": {"pass": "routes"},
                     "*:7081": {"pass": "routes"},
                 },
-                "routes": [{"action": {"share": temp_dir + "/assets$uri"}}],
+                "routes": [{"action": {"share": f'{assets_dir}$uri'}}],
                 "applications": {},
             }
         )
@@ -30,7 +31,7 @@ class TestStaticFallback(TestApplicationProto):
         yield
 
         try:
-            os.chmod(temp_dir + '/assets/403', 0o777)
+            os.chmod(f'{assets_dir}/403', 0o777)
         except FileNotFoundError:
             pass
 
@@ -49,7 +50,7 @@ class TestStaticFallback(TestApplicationProto):
 
     def test_static_fallback_valid_path(self, temp_dir):
         self.action_update(
-            {"share": temp_dir + "/assets$uri", "fallback": {"return": 200}}
+            {"share": f"{temp_dir}/assets$uri", "fallback": {"return": 200}}
         )
         resp = self.get()
         assert resp['status'] == 200, 'fallback status'
@@ -84,7 +85,7 @@ class TestStaticFallback(TestApplicationProto):
         self.action_update(
             {
                 "share": "/blah",
-                "fallback": {"share": temp_dir + "/assets$uri"},
+                "fallback": {"share": f"{temp_dir}/assets$uri"},
             }
         )
 

test/test_static_mount.py

@@ -14,20 +14,20 @@ class TestStaticMount(TestApplicationProto):
         if not is_su:
             pytest.skip('requires root')
 
-        os.makedirs(temp_dir + '/assets/dir/mount')
-        os.makedirs(temp_dir + '/assets/dir/dir')
-        os.makedirs(temp_dir + '/assets/mount')
-        Path(temp_dir + '/assets/index.html').write_text('index')
-        Path(temp_dir + '/assets/dir/dir/file').write_text('file')
-        Path(temp_dir + '/assets/mount/index.html').write_text('mount')
+        os.makedirs(f'{temp_dir}/assets/dir/mount')
+        os.makedirs(f'{temp_dir}/assets/dir/dir')
+        os.makedirs(f'{temp_dir}/assets/mount')
+        Path(f'{temp_dir}/assets/index.html').write_text('index')
+        Path(f'{temp_dir}/assets/dir/dir/file').write_text('file')
+        Path(f'{temp_dir}/assets/mount/index.html').write_text('mount')
 
         try:
             subprocess.check_output(
                 [
                     "mount",
                     "--bind",
-                    temp_dir + "/assets/mount",
-                    temp_dir + "/assets/dir/mount",
+                    f'{temp_dir}/assets/mount',
+                    f'{temp_dir}/assets/dir/mount',
                 ],
                 stderr=subprocess.STDOUT,
             )
@@ -36,12 +36,12 @@ class TestStaticMount(TestApplicationProto):
             raise
 
         except subprocess.CalledProcessError:
-            pytest.fail('Can\'t run mount process.')
+            pytest.fail("Can't run mount process.")
 
         self._load_conf(
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
-                "routes": [{"action": {"share": temp_dir + "/assets/dir$uri"}}],
+                "routes": [{"action": {"share": f'{temp_dir}/assets/dir$uri'}}],
             }
         )
 
@@ -49,7 +49,7 @@ class TestStaticMount(TestApplicationProto):
 
         try:
             subprocess.check_output(
-                ["umount", "--lazy", temp_dir + "/assets/dir/mount"],
+                ["umount", "--lazy", f'{temp_dir}/assets/dir/mount'],
                 stderr=subprocess.STDOUT,
             )
 
@@ -57,7 +57,7 @@ class TestStaticMount(TestApplicationProto):
             raise
 
         except subprocess.CalledProcessError:
-            pytest.fail('Can\'t run umount process.')
+            pytest.fail("Can't run umount process.")
 
     def test_static_mount(self, temp_dir, skip_alert):
         skip_alert(r'opening.*failed')
@@ -67,14 +67,14 @@ class TestStaticMount(TestApplicationProto):
         assert resp['body'] == 'mount'
 
         assert 'success' in self.conf(
-            {"share": temp_dir + "/assets/dir$uri", "traverse_mounts": False},
+            {"share": f'{temp_dir}/assets/dir$uri', "traverse_mounts": False},
             'routes/0/action',
         ), 'configure mount disable'
 
         assert self.get(url='/mount/')['status'] == 403
 
         assert 'success' in self.conf(
-            {"share": temp_dir + "/assets/dir$uri", "traverse_mounts": True},
+            {"share": f'{temp_dir}/assets/dir$uri', "traverse_mounts": True},
             'routes/0/action',
         ), 'configure mount enable'
 
@@ -85,21 +85,21 @@ class TestStaticMount(TestApplicationProto):
     def test_static_mount_two_blocks(self, temp_dir, skip_alert):
         skip_alert(r'opening.*failed')
 
-        os.symlink(temp_dir + '/assets/dir', temp_dir + '/assets/link')
+        os.symlink(f'{temp_dir}/assets/dir', f'{temp_dir}/assets/link')
 
         assert 'success' in self.conf(
             [
                 {
                     "match": {"method": "HEAD"},
                     "action": {
-                        "share": temp_dir + "/assets/dir$uri",
+                        "share": f'{temp_dir}/assets/dir$uri',
                         "traverse_mounts": False,
                     },
                 },
                 {
                     "match": {"method": "GET"},
                     "action": {
-                        "share": temp_dir + "/assets/dir$uri",
+                        "share": f'{temp_dir}/assets/dir$uri',
                         "traverse_mounts": True,
                     },
                 },
@@ -115,8 +115,8 @@ class TestStaticMount(TestApplicationProto):
 
         assert 'success' in self.conf(
             {
-                "share": temp_dir + "/assets/dir$uri",
-                "chroot": temp_dir + "/assets",
+                "share": f'{temp_dir}/assets/dir$uri',
+                "chroot": f'{temp_dir}/assets',
             },
             'routes/0/action',
         ), 'configure chroot mount default'
@@ -125,8 +125,8 @@ class TestStaticMount(TestApplicationProto):
 
         assert 'success' in self.conf(
             {
-                "share": temp_dir + "/assets/dir$uri",
-                "chroot": temp_dir + "/assets",
+                "share": f'{temp_dir}/assets/dir$uri',
+                "chroot": f'{temp_dir}/assets',
                 "traverse_mounts": False,
             },
             'routes/0/action',

test/test_static_share.py

@@ -10,16 +10,16 @@ class TestStaticShare(TestApplicationProto):
 
     @pytest.fixture(autouse=True)
     def setup_method_fixture(self, temp_dir):
-        os.makedirs(temp_dir + '/assets/dir')
-        os.makedirs(temp_dir + '/assets/dir2')
+        os.makedirs(f'{temp_dir}/assets/dir')
+        os.makedirs(f'{temp_dir}/assets/dir2')
 
-        Path(temp_dir + '/assets/dir/file').write_text('1')
-        Path(temp_dir + '/assets/dir2/file2').write_text('2')
+        Path(f'{temp_dir}/assets/dir/file').write_text('1')
+        Path(f'{temp_dir}/assets/dir2/file2').write_text('2')
 
         assert 'success' in self.conf(
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
-                "routes": [{"action": {"share": temp_dir + "/assets$uri"}}],
+                "routes": [{"action": {"share": f'{temp_dir}/assets$uri'}}],
                 "applications": {},
             }
         )
@@ -31,7 +31,7 @@ class TestStaticShare(TestApplicationProto):
         assert self.get(url='/dir/file')['body'] == '1'
         assert self.get(url='/dir2/file2')['body'] == '2'
 
-        self.action_update({"share": [temp_dir + "/assets/dir$uri"]})
+        self.action_update({"share": [f'{temp_dir}/assets/dir$uri']})
 
         assert self.get(url='/file')['body'] == '1'
         assert self.get(url='/file2')['status'] == 404
@@ -39,8 +39,8 @@ class TestStaticShare(TestApplicationProto):
         self.action_update(
             {
                 "share": [
-                    temp_dir + "/assets/dir$uri",
-                    temp_dir + "/assets/dir2$uri",
+                    f'{temp_dir}/assets/dir$uri',
+                    f'{temp_dir}/assets/dir2$uri',
                 ]
             }
         )
@@ -51,8 +51,8 @@ class TestStaticShare(TestApplicationProto):
         self.action_update(
             {
                 "share": [
-                    temp_dir + "/assets/dir2$uri",
-                    temp_dir + "/assets/dir3$uri",
+                    f'{temp_dir}/assets/dir2$uri',
+                    f'{temp_dir}/assets/dir3$uri',
                 ]
             }
         )

test/test_static_symlink.py

@@ -10,21 +10,21 @@ class TestStaticSymlink(TestApplicationProto):
 
     @pytest.fixture(autouse=True)
     def setup_method_fixture(self, temp_dir):
-        os.makedirs(temp_dir + '/assets/dir/dir')
-        Path(temp_dir + '/assets/index.html').write_text('0123456789')
-        Path(temp_dir + '/assets/dir/file').write_text('blah')
+        os.makedirs(f'{temp_dir}/assets/dir/dir')
+        Path(f'{temp_dir}/assets/index.html').write_text('0123456789')
+        Path(f'{temp_dir}/assets/dir/file').write_text('blah')
 
         self._load_conf(
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
-                "routes": [{"action": {"share": temp_dir + "/assets$uri"}}],
+                "routes": [{"action": {"share": f'{temp_dir}/assets$uri'}}],
             }
         )
 
     def test_static_symlink(self, temp_dir, skip_alert):
         skip_alert(r'opening.*failed')
 
-        os.symlink(temp_dir + '/assets/dir', temp_dir + '/assets/link')
+        os.symlink(f'{temp_dir}/assets/dir', f'{temp_dir}/assets/link')
 
         assert self.get(url='/dir')['status'] == 301, 'dir'
         assert self.get(url='/dir/file')['status'] == 200, 'file'
@@ -32,14 +32,14 @@ class TestStaticSymlink(TestApplicationProto):
         assert self.get(url='/link/file')['status'] == 200, 'symlink file'
 
         assert 'success' in self.conf(
-            {"share": temp_dir + "/assets$uri", "follow_symlinks": False},
+            {"share": f'{temp_dir}/assets$uri', "follow_symlinks": False},
             'routes/0/action',
         ), 'configure symlink disable'
 
         assert self.get(url='/link/file')['status'] == 403, 'symlink disabled'
 
         assert 'success' in self.conf(
-            {"share": temp_dir + "/assets$uri", "follow_symlinks": True},
+            {"share": f'{temp_dir}/assets$uri', "follow_symlinks": True},
             'routes/0/action',
         ), 'configure symlink enable'
 
@@ -48,21 +48,21 @@ class TestStaticSymlink(TestApplicationProto):
     def test_static_symlink_two_blocks(self, temp_dir, skip_alert):
         skip_alert(r'opening.*failed')
 
-        os.symlink(temp_dir + '/assets/dir', temp_dir + '/assets/link')
+        os.symlink(f'{temp_dir}/assets/dir', f'{temp_dir}/assets/link')
 
         assert 'success' in self.conf(
             [
                 {
                     "match": {"method": "HEAD"},
                     "action": {
-                        "share": temp_dir + "/assets$uri",
+                        "share": f'{temp_dir}/assets$uri',
                         "follow_symlinks": False,
                     },
                 },
                 {
                     "match": {"method": "GET"},
                     "action": {
-                        "share": temp_dir + "/assets$uri",
+                        "share": f'{temp_dir}/assets$uri',
                         "follow_symlinks": True,
                     },
                 },
@@ -77,15 +77,15 @@ class TestStaticSymlink(TestApplicationProto):
         skip_alert(r'opening.*failed')
 
         os.symlink(
-            temp_dir + '/assets/dir/file', temp_dir + '/assets/dir/dir/link'
+            f'{temp_dir}/assets/dir/file', f'{temp_dir}/assets/dir/dir/link'
         )
 
         assert self.get(url='/dir/dir/link')['status'] == 200, 'default chroot'
 
         assert 'success' in self.conf(
             {
-                "share": temp_dir + "/assets$uri",
-                "chroot": temp_dir + "/assets/dir/dir",
+                "share": f'{temp_dir}/assets$uri',
+                "chroot": f'{temp_dir}/assets/dir/dir',
             },
             'routes/0/action',
         ), 'configure chroot'

test/test_static_types.py

@@ -9,11 +9,11 @@ class TestStaticTypes(TestApplicationProto):
 
     @pytest.fixture(autouse=True)
     def setup_method_fixture(self, temp_dir):
-        Path(temp_dir + '/assets').mkdir()
+        Path(f'{temp_dir}/assets').mkdir()
         for ext in ['.xml', '.mp4', '.php', '', '.txt', '.html', '.png']:
-            Path(temp_dir + '/assets/file' + ext).write_text(ext)
+            Path(f'{temp_dir}/assets/file{ext}').write_text(ext)
 
-        Path(temp_dir + '/assets/index.html').write_text('index')
+        Path(f'{temp_dir}/assets/index.html').write_text('index')
 
         self._load_conf(
             {
@@ -21,7 +21,7 @@ class TestStaticTypes(TestApplicationProto):
                     "*:7080": {"pass": "routes"},
                     "*:7081": {"pass": "routes"},
                 },
-                "routes": [{"action": {"share": temp_dir + "/assets$uri"}}],
+                "routes": [{"action": {"share": f'{temp_dir}/assets$uri'}}],
                 "applications": {},
             }
         )
@@ -35,39 +35,39 @@ class TestStaticTypes(TestApplicationProto):
         assert resp['body'] == body, 'body'
 
     def test_static_types_basic(self, temp_dir):
-        self.action_update({"share": temp_dir + "/assets$uri"})
+        self.action_update({"share": f'{temp_dir}/assets$uri'})
         self.check_body('/index.html', 'index')
         self.check_body('/file.xml', '.xml')
 
         self.action_update(
-            {"share": temp_dir + "/assets$uri", "types": "application/xml"}
+            {"share": f'{temp_dir}/assets$uri', "types": "application/xml"}
         )
         self.check_body('/file.xml', '.xml')
 
         self.action_update(
-            {"share": temp_dir + "/assets$uri", "types": ["application/xml"]}
+            {"share": f'{temp_dir}/assets$uri', "types": ["application/xml"]}
         )
         self.check_body('/file.xml', '.xml')
 
-        self.action_update({"share": temp_dir + "/assets$uri", "types": [""]})
+        self.action_update({"share": f'{temp_dir}/assets$uri', "types": [""]})
         assert self.get(url='/file.xml')['status'] == 403, 'no mtype'
 
     def test_static_types_wildcard(self, temp_dir):
         self.action_update(
-            {"share": temp_dir + "/assets$uri", "types": ["application/*"]}
+            {"share": f'{temp_dir}/assets$uri', "types": ["application/*"]}
         )
         self.check_body('/file.xml', '.xml')
         assert self.get(url='/file.mp4')['status'] == 403, 'app * mtype mp4'
 
         self.action_update(
-            {"share": temp_dir + "/assets$uri", "types": ["video/*"]}
+            {"share": f'{temp_dir}/assets$uri', "types": ["video/*"]}
         )
         assert self.get(url='/file.xml')['status'] == 403, 'video * mtype xml'
         self.check_body('/file.mp4', '.mp4')
 
     def test_static_types_negation(self, temp_dir):
         self.action_update(
-            {"share": temp_dir + "/assets$uri", "types": ["!application/xml"]}
+            {"share": f'{temp_dir}/assets$uri', "types": ["!application/xml"]}
         )
         assert self.get(url='/file.xml')['status'] == 403, 'forbidden negation'
         self.check_body('/file.mp4', '.mp4')
@@ -75,7 +75,7 @@ class TestStaticTypes(TestApplicationProto):
         # sorting negation
         self.action_update(
             {
-                "share": temp_dir + "/assets$uri",
+                "share": f'{temp_dir}/assets$uri',
                 "types": ["!video/*", "image/png", "!image/jpg"],
             }
         )
@@ -86,7 +86,7 @@ class TestStaticTypes(TestApplicationProto):
     def test_static_types_regex(self, temp_dir):
         self.action_update(
             {
-                "share": temp_dir + "/assets$uri",
+                "share": f'{temp_dir}/assets$uri',
                 "types": ["~text/(html|plain)"],
             }
         )
@@ -96,7 +96,7 @@ class TestStaticTypes(TestApplicationProto):
 
     def test_static_types_case(self, temp_dir):
         self.action_update(
-            {"share": temp_dir + "/assets$uri", "types": ["!APpliCaTiOn/xMl"]}
+            {"share": f'{temp_dir}/assets$uri', "types": ["!APpliCaTiOn/xMl"]}
         )
         self.check_body('/file.mp4', '.mp4')
         assert (
@@ -104,7 +104,7 @@ class TestStaticTypes(TestApplicationProto):
         ), 'mixed case xml negation'
 
         self.action_update(
-            {"share": temp_dir + "/assets$uri", "types": ["vIdEo/mp4"]}
+            {"share": f'{temp_dir}/assets$uri', "types": ["vIdEo/mp4"]}
         )
         assert self.get(url='/file.mp4')['status'] == 200, 'mixed case'
         assert (
@@ -112,7 +112,7 @@ class TestStaticTypes(TestApplicationProto):
         ), 'mixed case video negation'
 
         self.action_update(
-            {"share": temp_dir + "/assets$uri", "types": ["vIdEo/*"]}
+            {"share": f'{temp_dir}/assets$uri', "types": ["vIdEo/*"]}
         )
         self.check_body('/file.mp4', '.mp4')
         assert (
@@ -128,7 +128,7 @@ class TestStaticTypes(TestApplicationProto):
                 },
                 {
                     "action": {
-                        "share": temp_dir + "/assets$uri",
+                        "share": f'{temp_dir}/assets$uri',
                         "types": ["!application/x-httpd-php"],
                         "fallback": {"proxy": "http://127.0.0.1:7081"},
                     }
@@ -142,7 +142,7 @@ class TestStaticTypes(TestApplicationProto):
 
     def test_static_types_index(self, temp_dir):
         self.action_update(
-            {"share": temp_dir + "/assets$uri", "types": "application/xml"}
+            {"share": f'{temp_dir}/assets$uri', "types": "application/xml"}
         )
         self.check_body('/', 'index')
         self.check_body('/file.xml', '.xml')
@@ -153,7 +153,7 @@ class TestStaticTypes(TestApplicationProto):
         self._load_conf(
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
-                "routes": [{"action": {"share": temp_dir + "/assets$uri"}}],
+                "routes": [{"action": {"share": f'{temp_dir}/assets$uri'}}],
                 "applications": {},
                 "settings": {
                     "http": {
@@ -163,10 +163,10 @@ class TestStaticTypes(TestApplicationProto):
             }
         )
 
-        self.action_update({"share": temp_dir + "/assets$uri", "types": [""]})
+        self.action_update({"share": f'{temp_dir}/assets$uri', "types": [""]})
         assert self.get(url='/file')['status'] == 403, 'forbidden custom mime'
 
         self.action_update(
-            {"share": temp_dir + "/assets$uri", "types": ["test/mime-type"]}
+            {"share": f'{temp_dir}/assets$uri', "types": ["test/mime-type"]}
         )
         self.check_body('/file', '')

test/test_static_variables.py

@@ -10,16 +10,16 @@ class TestStaticVariables(TestApplicationProto):
 
     @pytest.fixture(autouse=True)
     def setup_method_fixture(self, temp_dir):
-        os.makedirs(temp_dir + '/assets/dir')
-        os.makedirs(temp_dir + '/assets/d$r')
-        Path(temp_dir + '/assets/index.html').write_text('0123456789')
-        Path(temp_dir + '/assets/dir/file').write_text('file')
-        Path(temp_dir + '/assets/d$r/file').write_text('d$r')
+        os.makedirs(f'{temp_dir}/assets/dir')
+        os.makedirs(f'{temp_dir}/assets/d$r')
+        Path(f'{temp_dir}/assets/index.html').write_text('0123456789')
+        Path(f'{temp_dir}/assets/dir/file').write_text('file')
+        Path(f'{temp_dir}/assets/d$r/file').write_text('d$r')
 
         self._load_conf(
             {
                 "listeners": {"*:7080": {"pass": "routes"}},
-                "routes": [{"action": {"share": temp_dir + "/assets$uri"}}],
+                "routes": [{"action": {"share": f'{temp_dir}/assets$uri'}}],
             }
         )
 
@@ -27,37 +27,37 @@ class TestStaticVariables(TestApplicationProto):
         if isinstance(share, list):
             return self.conf(share, 'routes/0/action/share')
 
-        return self.conf('"' + share + '"', 'routes/0/action/share')
+        return self.conf(f'"{share}"', 'routes/0/action/share')
 
     def test_static_variables(self, temp_dir):
         assert self.get(url='/index.html')['status'] == 200
         assert self.get(url='/d$r/file')['status'] == 200
 
         assert 'success' in self.update_share('$uri')
-        assert self.get(url=temp_dir + '/assets/index.html')['status'] == 200
+        assert self.get(url=f'{temp_dir}/assets/index.html')['status'] == 200
 
-        assert 'success' in self.update_share(temp_dir + '/assets${uri}')
+        assert 'success' in self.update_share(f'{temp_dir}/assets${{uri}}')
         assert self.get(url='/index.html')['status'] == 200
 
     def test_static_variables_array(self, temp_dir):
         assert 'success' in self.update_share(
-            [temp_dir + '/assets$uri', '$uri']
+            [f'{temp_dir}/assets$uri', '$uri']
         )
 
         assert self.get(url='/dir/file')['status'] == 200
-        assert self.get(url=temp_dir + '/assets/index.html')['status'] == 200
+        assert self.get(url=f'{temp_dir}/assets/index.html')['status'] == 200
         assert self.get(url='/blah')['status'] == 404
 
         assert 'success' in self.conf(
             {
-                "share": [temp_dir + '/assets$uri', '$uri'],
+                "share": [f'{temp_dir}/assets$uri', '$uri'],
                 "fallback": {"return": 201},
             },
             'routes/0/action',
         )
 
         assert self.get(url='/dir/file')['status'] == 200
-        assert self.get(url=temp_dir + '/assets/index.html')['status'] == 200
+        assert self.get(url=f'{temp_dir}/assets/index.html')['status'] == 200
         assert self.get(url='/dir/blah')['status'] == 201
 
     def test_static_variables_buildin_start(self, temp_dir):
@@ -65,15 +65,15 @@ class TestStaticVariables(TestApplicationProto):
         assert self.get(url=temp_dir)['status'] == 200
 
     def test_static_variables_buildin_mid(self, temp_dir):
-        assert 'success' in self.update_share(temp_dir + '$uri/index.html')
+        assert 'success' in self.update_share(f'{temp_dir}$uri/index.html')
         assert self.get(url='/assets')['status'] == 200
 
     def test_static_variables_buildin_end(self):
         assert self.get(url='/index.html')['status'] == 200
 
     def test_static_variables_invalid(self, temp_dir):
-        assert 'error' in self.update_share(temp_dir + '/assets/d$r$uri')
-        assert 'error' in self.update_share(temp_dir + '/assets/$$uri')
+        assert 'error' in self.update_share(f'{temp_dir}/assets/d$r$uri')
+        assert 'error' in self.update_share(f'{temp_dir}/assets/$$uri')
         assert 'error' in self.update_share(
-            [temp_dir + '/assets$uri', temp_dir + '/assets/dir', '$$uri']
+            [f'{temp_dir}/assets$uri', f'{temp_dir}/assets/dir', '$$uri']
         )

test/test_status.py

@@ -18,11 +18,12 @@ class TestStatus(TestApplicationPython):
         }
 
     def app_default(self, name="empty", module="wsgi"):
+        name_dir = f'{option.test_dir}/python/{name}'
         return {
             "type": self.get_application_type(),
             "processes": {"spare": 0},
-            "path": option.test_dir + "/python/" + name,
-            "working_directory": option.test_dir + "/python/" + name,
+            "path": name_dir,
+            "working_directory": name_dir,
             "module": module,
         }
 
@@ -141,7 +142,7 @@ Connection: close
             assert apps == expert.sort()
 
         def check_application(name, running, starting, idle, active):
-            Status.get('/applications/' + name) == {
+            Status.get(f'/applications/{name}') == {
                 'processes': {
                     'running': running,
                     'starting': starting,

test/test_tls.py

@@ -17,19 +17,19 @@ class TestTLS(TestApplicationTLS):
     def add_tls(self, application='empty', cert='default', port=7080):
         assert 'success' in self.conf(
             {
-                "pass": "applications/" + application,
+                "pass": f"applications/{application}",
                 "tls": {"certificate": cert},
             },
-            'listeners/*:' + str(port),
+            f'listeners/*:{port}',
         )
 
     def remove_tls(self, application='empty', port=7080):
         assert 'success' in self.conf(
-            {"pass": "applications/" + application}, 'listeners/*:' + str(port)
+            {"pass": f"applications/{application}"}, f'listeners/*:{port}'
         )
 
     def req(self, name='localhost', subject=None, x509=False):
-        subj = subject if subject is not None else '/CN=' + name + '/'
+        subj = subject if subject is not None else f'/CN={name}/'
 
         subprocess.check_output(
             [
@@ -39,27 +39,27 @@ class TestTLS(TestApplicationTLS):
                 '-subj',
                 subj,
                 '-config',
-                option.temp_dir + '/openssl.conf',
+                f'{option.temp_dir}/openssl.conf',
                 '-out',
-                option.temp_dir + '/' + name + '.csr',
+                f'{option.temp_dir}/{name}.csr',
                 '-keyout',
-                option.temp_dir + '/' + name + '.key',
+                f'{option.temp_dir}/{name}.key',
             ],
             stderr=subprocess.STDOUT,
         )
 
     def generate_ca_conf(self):
-        with open(option.temp_dir + '/ca.conf', 'w') as f:
+        with open(f'{option.temp_dir}/ca.conf', 'w') as f:
             f.write(
-                """[ ca ]
+                f"""[ ca ]
 default_ca = myca
 
 [ myca ]
-new_certs_dir = %(dir)s
-database = %(database)s
+new_certs_dir = {option.temp_dir}
+database = {option.temp_dir}/certindex
 default_md = sha256
 policy = myca_policy
-serial = %(certserial)s
+serial = {option.temp_dir}/certserial
 default_days = 1
 x509_extensions = myca_extensions
 copy_extensions = copy
@@ -69,20 +69,15 @@ commonName = optional
 
 [ myca_extensions ]
 basicConstraints = critical,CA:TRUE"""
-                % {
-                    'dir': option.temp_dir,
-                    'database': option.temp_dir + '/certindex',
-                    'certserial': option.temp_dir + '/certserial',
-                }
             )
 
-        with open(option.temp_dir + '/certserial', 'w') as f:
+        with open(f'{option.temp_dir}/certserial', 'w') as f:
             f.write('1000')
 
-        with open(option.temp_dir + '/certindex', 'w') as f:
+        with open(f'{option.temp_dir}/certindex', 'w') as f:
             f.write('')
 
-        with open(option.temp_dir + '/certindex.attr', 'w') as f:
+        with open(f'{option.temp_dir}/certindex.attr', 'w') as f:
             f.write('')
 
     def ca(self, cert='root', out='localhost'):
@@ -92,15 +87,15 @@ basicConstraints = critical,CA:TRUE"""
                 'ca',
                 '-batch',
                 '-config',
-                option.temp_dir + '/ca.conf',
+                f'{option.temp_dir}/ca.conf',
                 '-keyfile',
-                option.temp_dir + '/' + cert + '.key',
+                f'{option.temp_dir}/{cert}.key',
                 '-cert',
-                option.temp_dir + '/' + cert + '.crt',
+                f'{option.temp_dir}/{cert}.crt',
                 '-in',
-                option.temp_dir + '/' + out + '.csr',
+                f'{option.temp_dir}/{out}.csr',
                 '-out',
-                option.temp_dir + '/' + out + '.crt',
+                f'{option.temp_dir}/{out}.crt',
             ],
             stderr=subprocess.STDOUT,
         )
@@ -109,9 +104,7 @@ basicConstraints = critical,CA:TRUE"""
         self.context = ssl.create_default_context()
         self.context.check_hostname = False
         self.context.verify_mode = ssl.CERT_REQUIRED
-        self.context.load_verify_locations(
-            option.temp_dir + '/' + cert + '.crt'
-        )
+        self.context.load_verify_locations(f'{option.temp_dir}/{cert}.crt')
 
     def test_tls_listener_option_add(self):
         self.load('empty')
@@ -230,7 +223,7 @@ basicConstraints = critical,CA:TRUE"""
                 '-noout',
                 '-genkey',
                 '-out',
-                temp_dir + '/ec.key',
+                f'{temp_dir}/ec.key',
                 '-name',
                 'prime256v1',
             ],
@@ -246,11 +239,11 @@ basicConstraints = critical,CA:TRUE"""
                 '-subj',
                 '/CN=ec/',
                 '-config',
-                temp_dir + '/openssl.conf',
+                f'{temp_dir}/openssl.conf',
                 '-key',
-                temp_dir + '/ec.key',
+                f'{temp_dir}/ec.key',
                 '-out',
-                temp_dir + '/ec.crt',
+                f'{temp_dir}/ec.crt',
             ],
             stderr=subprocess.STDOUT,
         )
@@ -305,9 +298,9 @@ basicConstraints = critical,CA:TRUE"""
         self.ca(cert='root', out='int')
         self.ca(cert='int', out='end')
 
-        crt_path = temp_dir + '/end-int.crt'
-        end_path = temp_dir + '/end.crt'
-        int_path = temp_dir + '/int.crt'
+        crt_path = f'{temp_dir}/end-int.crt'
+        end_path = f'{temp_dir}/end.crt'
+        int_path = f'{temp_dir}/int.crt'
 
         with open(crt_path, 'wb') as crt, open(end_path, 'rb') as end, open(
             int_path, 'rb'
@@ -400,22 +393,24 @@ basicConstraints = critical,CA:TRUE"""
             elif i == chain_length - 1:
                 self.req('end')
             else:
-                self.req('int{}'.format(i))
+                self.req(f'int{i}')
 
         for i in range(chain_length - 1):
             if i == 0:
                 self.ca(cert='root', out='int1')
             elif i == chain_length - 2:
-                self.ca(cert='int{}'.format(chain_length - 2), out='end')
+                self.ca(cert=f'int{(chain_length - 2)}', out='end')
             else:
-                self.ca(cert='int{}'.format(i), out='int{}'.format(i + 1))
+                self.ca(cert=f'int{i}', out=f'int{(i + 1)}')
 
         for i in range(chain_length - 1, 0, -1):
-            path = temp_dir + (
-                '/end.crt' if i == chain_length - 1 else '/int{}.crt'.format(i)
+            path = (
+                f'{temp_dir}/end.crt'
+                if i == chain_length - 1
+                else f'{temp_dir}/int{i}.crt'
             )
 
-            with open(temp_dir + '/all.crt', 'a') as chain, open(path) as cert:
+            with open(f'{temp_dir}/all.crt', 'a') as chain, open(path) as cert:
                 chain.write(cert.read())
 
         self.set_certificate_req_context()
@@ -611,10 +606,10 @@ basicConstraints = critical,CA:TRUE"""
 
         subprocess.check_output(['kill', '-9', app_id])
 
-        skip_alert(r'process %s exited on signal 9' % app_id)
+        skip_alert(fr'process {app_id} exited on signal 9')
 
         self.wait_for_record(
-            r' (?!' + app_id + r'#)(\d+)#\d+ "mirror" application started'
+            fr' (?!{app_id}#)(\d+)#\d+ "mirror" application started'
         )
 
         resp = self.post_ssl(sock=sock, body='0123456789')
@@ -673,7 +668,7 @@ basicConstraints = critical,CA:TRUE"""
             }
         )
         assert res['status'] == 200, 'status ok'
-        assert res['body'] == filename + data
+        assert res['body'] == f'{filename}{data}'
 
     def test_tls_multi_listener(self):
         self.load('empty')

test/test_tls_conf_command.py

@@ -47,7 +47,7 @@ class TestTLSConfCommand(TestApplicationTLS):
         assert 'success' in self.conf(
             {
                 "certificate": "default",
-                "conf_commands": {"protocol": '-' + protocol},
+                "conf_commands": {"protocol": f'-{protocol}'},
             },
             'listeners/*:7080/tls',
         ), 'protocol disabled'
@@ -74,8 +74,8 @@ class TestTLSConfCommand(TestApplicationTLS):
             {
                 "certificate": "default",
                 "conf_commands": {
-                    "protocol": '-' + protocol,
-                    "cipherstring": cipher[1] + ":!" + cipher[0],
+                    "protocol": f'-{protocol}',
+                    "cipherstring": f"{cipher[1]}:!{cipher[0]}",
                 },
             },
             'listeners/*:7080/tls',

test/test_tls_sni.py

@@ -30,17 +30,17 @@ class TestTLSSNI(TestApplicationTLS):
         assert 'success' in self.conf({"pass": "routes"}, 'listeners/*:7080')
 
     def generate_ca_conf(self):
-        with open(option.temp_dir + '/ca.conf', 'w') as f:
+        with open(f'{option.temp_dir}/ca.conf', 'w') as f:
             f.write(
-                """[ ca ]
+                f"""[ ca ]
 default_ca = myca
 
 [ myca ]
-new_certs_dir = %(dir)s
-database = %(database)s
+new_certs_dir = {option.temp_dir}
+database = {option.temp_dir}/certindex
 default_md = sha256
 policy = myca_policy
-serial = %(certserial)s
+serial = {option.temp_dir}/certserial
 default_days = 1
 x509_extensions = myca_extensions
 copy_extensions = copy
@@ -50,17 +50,12 @@ commonName = optional
 
 [ myca_extensions ]
 basicConstraints = critical,CA:TRUE"""
-                % {
-                    'dir': option.temp_dir,
-                    'database': option.temp_dir + '/certindex',
-                    'certserial': option.temp_dir + '/certserial',
-                }
             )
 
-        with open(option.temp_dir + '/certserial', 'w') as f:
+        with open(f'{option.temp_dir}/certserial', 'w') as f:
             f.write('1000')
 
-        with open(option.temp_dir + '/certindex', 'w') as f:
+        with open(f'{option.temp_dir}/certindex', 'w') as f:
             f.write('')
 
     def config_bundles(self, bundles):
@@ -68,11 +63,7 @@ basicConstraints = critical,CA:TRUE"""
 
         for b in bundles:
             self.openssl_conf(rewrite=True, alt_names=bundles[b]['alt_names'])
-            subj = (
-                '/CN={}/'.format(bundles[b]['subj'])
-                if 'subj' in bundles[b]
-                else '/'
-            )
+            subj = f'/CN={bundles[b]["subj"]}/' if 'subj' in bundles[b] else '/'
 
             subprocess.check_output(
                 [
@@ -82,11 +73,11 @@ basicConstraints = critical,CA:TRUE"""
                     '-subj',
                     subj,
                     '-config',
-                    option.temp_dir + '/openssl.conf',
+                    f'{option.temp_dir}/openssl.conf',
                     '-out',
-                    option.temp_dir + '/{}.csr'.format(b),
+                    f'{option.temp_dir}/{b}.csr',
                     '-keyout',
-                    option.temp_dir + '/{}.key'.format(b),
+                    f'{option.temp_dir}/{b}.key',
                 ],
                 stderr=subprocess.STDOUT,
             )
@@ -94,11 +85,7 @@ basicConstraints = critical,CA:TRUE"""
         self.generate_ca_conf()
 
         for b in bundles:
-            subj = (
-                '/CN={}/'.format(bundles[b]['subj'])
-                if 'subj' in bundles[b]
-                else '/'
-            )
+            subj = f'/CN={bundles[b]["subj"]}/' if 'subj' in bundles[b] else '/'
 
             subprocess.check_output(
                 [
@@ -108,15 +95,15 @@ basicConstraints = critical,CA:TRUE"""
                     '-subj',
                     subj,
                     '-config',
-                    option.temp_dir + '/ca.conf',
+                    f'{option.temp_dir}/ca.conf',
                     '-keyfile',
-                    option.temp_dir + '/root.key',
+                    f'{option.temp_dir}/root.key',
                     '-cert',
-                    option.temp_dir + '/root.crt',
+                    f'{option.temp_dir}/root.crt',
                     '-in',
-                    option.temp_dir + '/{}.csr'.format(b),
+                    f'{option.temp_dir}/{b}.csr',
                     '-out',
-                    option.temp_dir + '/{}.crt'.format(b),
+                    f'{option.temp_dir}/{b}.crt',
                 ],
                 stderr=subprocess.STDOUT,
             )
@@ -124,7 +111,7 @@ basicConstraints = critical,CA:TRUE"""
         self.context = ssl.create_default_context()
         self.context.check_hostname = False
         self.context.verify_mode = ssl.CERT_REQUIRED
-        self.context.load_verify_locations(option.temp_dir + '/root.crt')
+        self.context.load_verify_locations(f'{option.temp_dir}/root.crt')
 
         self.load_certs(bundles)
 
@@ -132,7 +119,7 @@ basicConstraints = critical,CA:TRUE"""
         for bname, bvalue in bundles.items():
             assert 'success' in self.certificate_load(
                 bname, bname
-            ), 'certificate {} upload'.format(bvalue['subj'])
+            ), f'certificate {bvalue["subj"]} upload'
 
     def check_cert(self, host, expect):
         resp, sock = self.get_ssl(

test/test_tls_tickets.py

@@ -48,7 +48,7 @@ class TestTLSTicket(TestApplicationTLS):
     def set_tickets(self, tickets=True, port=7080):
         assert 'success' in self.conf(
             {"cache_size": 0, "tickets": tickets},
-            'listeners/*:' + str(port) + '/tls/session',
+            f'listeners/*:{port}/tls/session',
         )
 
     def connect(self, ctx=None, session=None, port=7080):
@@ -168,7 +168,7 @@ class TestTLSTicket(TestApplicationTLS):
             'listeners/*:7080/tls/session/tickets/0'
         ), 'removed first ticket'
         assert 'success' in self.conf_post(
-            '"' + self.ticket + '"', 'listeners/*:7080/tls/session/tickets'
+            f'"{self.ticket}"', 'listeners/*:7080/tls/session/tickets'
         ), 'add new ticket to the end of array'
 
         sess, ctx, _ = self.connect()
@@ -186,10 +186,10 @@ class TestTLSTicket(TestApplicationTLS):
 
         check_tickets({})
         check_tickets('!?&^' * 16)
-        check_tickets(self.ticket[:-2] + '!' + self.ticket[3:])
+        check_tickets(f'{self.ticket[:-2]}!{self.ticket[3:]}')
         check_tickets(self.ticket[:-1])
-        check_tickets(self.ticket + 'b')
-        check_tickets(self.ticket + 'blah')
+        check_tickets(f'{self.ticket}b')
+        check_tickets(f'{self.ticket}blah')
         check_tickets([True, self.ticket, self.ticket2])
         check_tickets([self.ticket, 'blah', self.ticket2])
         check_tickets([self.ticket, self.ticket2, []])

test/test_unix_abstract.py

@@ -13,14 +13,14 @@ class TestUnixAbstract(TestApplicationPython):
 
         def source(source):
             assert 'success' in self.conf(
-                '"' + source + '"', 'routes/0/match/source'
+                f'"{source}"', 'routes/0/match/source'
             )
 
         assert 'success' in self.conf(
             {
                 "listeners": {
                     "127.0.0.1:7080": {"pass": "routes"},
-                    "unix:@" + addr[1:]: {"pass": "routes"},
+                    f"unix:@{addr[1:]}": {"pass": "routes"},
                 },
                 "routes": [
                     {
@@ -61,6 +61,7 @@ class TestUnixAbstract(TestApplicationPython):
                 headers={'Connection': 'close', 'X-Forwarded-For': xff},
             )['body']
 
+        client_ip_dir = f"{option.test_dir}/python/client_ip"
         assert 'success' in self.conf(
             {
                 "listeners": {
@@ -90,9 +91,8 @@ class TestUnixAbstract(TestApplicationPython):
                     "client_ip": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "path": option.test_dir + "/python/client_ip",
-                        "working_directory": option.test_dir
-                        + "/python/client_ip",
+                        "path": client_ip_dir,
+                        "working_directory": client_ip_dir,
                         "module": "wsgi",
                     }
                 },

test/test_upstreams_rr.py

@@ -247,6 +247,7 @@ Connection: close
         assert abs(r_two[0] - r_two[1]) <= self.cpu_count, 'dep two mix'
 
     def test_upstreams_rr_delay(self):
+        delayed_dir = f'{option.test_dir}/python/delayed'
         assert 'success' in self.conf(
             {
                 "listeners": {
@@ -276,9 +277,8 @@ Connection: close
                     "delayed": {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "path": option.test_dir + "/python/delayed",
-                        "working_directory": option.test_dir
-                        + "/python/delayed",
+                        "path": delayed_dir,
+                        "working_directory": delayed_dir,
                         "module": "wsgi",
                     }
                 },
@@ -389,20 +389,20 @@ Connection: close
         assert abs(resps[0] - resps[1]) <= self.cpu_count, 'post'
 
     def test_upstreams_rr_unix(self, temp_dir):
-        addr_0 = temp_dir + '/sock_0'
-        addr_1 = temp_dir + '/sock_1'
+        addr_0 = f'{temp_dir}/sock_0'
+        addr_1 = f'{temp_dir}/sock_1'
 
         assert 'success' in self.conf(
             {
                 "*:7080": {"pass": "upstreams/one"},
-                "unix:" + addr_0: {"pass": "routes/one"},
-                "unix:" + addr_1: {"pass": "routes/two"},
+                f"unix:{addr_0}": {"pass": "routes/one"},
+                f"unix:{addr_1}": {"pass": "routes/two"},
             },
             'listeners',
         ), 'configure listeners unix'
 
         assert 'success' in self.conf(
-            {"unix:" + addr_0: {}, "unix:" + addr_1: {}},
+            {f"unix:{addr_0}": {}, f"unix:{addr_1}": {}},
             'upstreams/one/servers',
         ), 'configure servers unix'
 

test/test_usr1.py

@@ -14,15 +14,15 @@ class TestUSR1(TestApplicationPython):
 
         log = 'access.log'
         log_new = 'new.log'
-        log_path = temp_dir + '/' + log
+        log_path = f'{temp_dir}/{log}'
 
         assert 'success' in self.conf(
-            '"' + log_path + '"', 'access_log'
+            f'"{log_path}"', 'access_log'
         ), 'access log configure'
 
         assert waitforfiles(log_path), 'open'
 
-        os.rename(log_path, temp_dir + '/' + log_new)
+        os.rename(log_path, f'{temp_dir}/{log_new}')
 
         assert self.get()['status'] == 200
 
@@ -48,8 +48,8 @@ class TestUSR1(TestApplicationPython):
         self.load('log_body')
 
         log_new = 'new.log'
-        log_path = temp_dir + '/unit.log'
-        log_path_new = temp_dir + '/' + log_new
+        log_path = f'{temp_dir}/unit.log'
+        log_path_new = f'{temp_dir}/{log_new}'
 
         os.rename(log_path, log_path_new)
 

test/test_variables.py

@@ -19,7 +19,7 @@ class TestVariables(TestApplicationProto):
     def set_format(self, format):
         assert 'success' in self.conf(
             {
-                'path': option.temp_dir + '/access.log',
+                'path': f'{option.temp_dir}/access.log',
                 'format': format,
             },
             'access_log',
@@ -36,7 +36,7 @@ class TestVariables(TestApplicationProto):
 
         def check_dollar(location, expect):
             assert 'success' in self.conf(
-                '"' + location + '"',
+                f'"{location}"',
                 'routes/0/action/location',
             )
             assert self.get()['headers']['Location'] == expect
@@ -93,7 +93,7 @@ Connection: close
         self.set_format('$request_uri')
 
         def check_request_uri(req_uri):
-            reg = r'^' + re.escape(req_uri) + r'$'
+            reg = fr'^{re.escape(req_uri)}$'
 
             assert self.search_in_log(reg) is None
             assert self.get(url=req_uri)['status'] == 200
@@ -109,7 +109,7 @@ Connection: close
 
         def check_uri(uri, expect=None):
             expect = uri if expect is None else expect
-            reg = r'^' + re.escape(expect) + r'$'
+            reg = fr'^{re.escape(expect)}$'
 
             assert self.search_in_log(reg) is None
             assert self.get(url=uri)['status'] == 200
@@ -125,7 +125,7 @@ Connection: close
 
         def check_host(host, expect=None):
             expect = host if expect is None else expect
-            reg = r'^' + re.escape(expect) + r'$'
+            reg = fr'^{re.escape(expect)}$'
 
             assert self.search_in_log(reg) is None
             assert (
@@ -196,7 +196,7 @@ Connection: close
         self.set_format('$method $header_referer')
 
         def check_referer(referer):
-            reg = r'^GET ' + re.escape(referer) + r'$'
+            reg = fr'^GET {re.escape(referer)}$'
 
             assert self.search_in_log(reg) is None
             assert (
@@ -219,7 +219,7 @@ Connection: close
         self.set_format('$method $header_user_agent')
 
         def check_user_agent(user_agent):
-            reg = r'^GET ' + re.escape(user_agent) + r'$'
+            reg = fr'^GET {re.escape(user_agent)}$'
 
             assert self.search_in_log(reg) is None
             assert (
@@ -240,7 +240,7 @@ Connection: close
 
     def test_variables_many(self):
         def check_vars(uri, expect):
-            reg = r'^' + re.escape(expect) + r'$'
+            reg = fr'^{re.escape(expect)}$'
 
             assert self.search_in_log(reg) is None
             assert self.get(url=uri)['status'] == 200
@@ -273,7 +273,7 @@ Connection: close
     def test_variables_dynamic_arguments(self):
         def check_arg(url, expect=None):
             expect = url if expect is None else expect
-            reg = r'^' + re.escape(expect) + r'$'
+            reg = fr'^{re.escape(expect)}$'
 
             assert self.search_in_log(reg) is None
             assert self.get(url=url)['status'] == 200
@@ -304,7 +304,7 @@ Connection: close
 
     def test_variables_dynamic_headers(self):
         def check_header(header, value):
-            reg = r'^' + value + r'$'
+            reg = fr'^{value}$'
 
             assert self.search_in_log(reg) is None
             assert (
@@ -368,7 +368,7 @@ Connection: close
         def check_variables(format):
             assert 'error' in self.conf(
                 {
-                    'path': option.temp_dir + '/access.log',
+                    'path': f'{option.temp_dir}/access.log',
                     'format': format,
                 },
                 'access_log',

test/unit/applications/lang/go.py

@@ -14,23 +14,21 @@ class TestApplicationGo(TestApplicationProto):
         except subprocess.CalledProcessError:
             return None
 
-        temp_dir = option.temp_dir + '/go/'
+        temp_dir = f'{option.temp_dir}/go/'
 
         if not os.path.exists(temp_dir):
             os.mkdir(temp_dir)
 
-        cache_dir = option.cache_dir + '/go-build'
+        cache_dir = f'{option.cache_dir}/go-build'
 
         if not os.path.exists(cache_dir):
             os.mkdir(cache_dir)
 
         env = os.environ.copy()
-        env['GOPATH'] = option.current_dir + '/build/go'
+        env['GOPATH'] = f'{option.current_dir}/build/go'
         env['GOCACHE'] = cache_dir
 
-        shutil.copy2(
-            option.test_dir + '/go/' + script + '/' + name + '.go', temp_dir
-        )
+        shutil.copy2(f'{option.test_dir}/go/{script}/{name}.go', temp_dir)
 
         if static:
             args = [
@@ -41,21 +39,21 @@ class TestApplicationGo(TestApplicationProto):
                 '-ldflags',
                 '-extldflags "-static"',
                 '-o',
-                temp_dir + name,
-                temp_dir + name + '.go',
+                f'{temp_dir}{name}',
+                f'{temp_dir}{name}.go',
             ]
         else:
             args = [
                 'go',
                 'build',
                 '-o',
-                temp_dir + name,
-                temp_dir + name + '.go',
+                f'{temp_dir}{name}',
+                f'{temp_dir}{name}.go',
             ]
 
-        replace_path = option.current_dir + '/build/go/src/unit.nginx.org/go'
+        replace_path = f'{option.current_dir}/build/go/src/unit.nginx.org/go'
 
-        with open(temp_dir + 'go.mod', 'w') as f:
+        with open(f'{temp_dir}go.mod', 'w') as f:
             f.write(
                 f"""module test/app
 require unit.nginx.org/go v0.0.0
@@ -64,7 +62,7 @@ replace unit.nginx.org/go => {replace_path}
             )
 
         if option.detailed:
-            print("\n$ GOPATH=" + env['GOPATH'] + " " + " ".join(args))
+            print(f'\n$ GOPATH={env["GOPATH"]} {" ".join(args)}')
 
         try:
             output = subprocess.check_output(
@@ -82,18 +80,18 @@ replace unit.nginx.org/go => {replace_path}
     def load(self, script, name='app', **kwargs):
         static_build = False
 
-        wdir = option.test_dir + "/go/" + script
-        executable = option.temp_dir + "/go/" + name
+        wdir = f'{option.test_dir}/go/{script}'
+        executable = f'{option.temp_dir}/go/{name}'
 
         if 'isolation' in kwargs and 'rootfs' in kwargs['isolation']:
             wdir = "/go/"
-            executable = "/go/" + name
+            executable = f"/go/{name}"
             static_build = True
 
         TestApplicationGo.prepare_env(script, name, static=static_build)
 
         conf = {
-            "listeners": {"*:7080": {"pass": "applications/" + script}},
+            "listeners": {"*:7080": {"pass": f"applications/{script}"}},
             "applications": {
                 script: {
                     "type": "external",

test/unit/applications/lang/java.py

@@ -12,10 +12,10 @@ class TestApplicationJava(TestApplicationProto):
     application_type = "java"
 
     def prepare_env(self, script):
-        app_path = option.temp_dir + '/java'
-        web_inf_path = app_path + '/WEB-INF/'
-        classes_path = web_inf_path + 'classes/'
-        script_path = option.test_dir + '/java/' + script + '/'
+        app_path = f'{option.temp_dir}/java'
+        web_inf_path = f'{app_path}/WEB-INF/'
+        classes_path = f'{web_inf_path}classes/'
+        script_path = f'{option.test_dir}/java/{script}/'
 
         if not os.path.isdir(app_path):
             os.makedirs(app_path)
@@ -23,7 +23,7 @@ class TestApplicationJava(TestApplicationProto):
         src = []
 
         for f in os.listdir(script_path):
-            file_path = script_path + f
+            file_path = f'{script_path}{f}'
 
             if f.endswith('.java'):
                 src.append(file_path)
@@ -36,7 +36,7 @@ class TestApplicationJava(TestApplicationProto):
                 if f == 'WEB-INF':
                     continue
 
-                shutil.copytree(file_path, app_path + '/' + f)
+                shutil.copytree(file_path, f'{app_path}/{f}')
                 continue
 
             if f == 'web.xml':
@@ -52,11 +52,11 @@ class TestApplicationJava(TestApplicationProto):
                 os.makedirs(classes_path)
 
             classpath = (
-                option.current_dir + '/build/tomcat-servlet-api-9.0.70.jar'
+                f'{option.current_dir}/build/tomcat-servlet-api-9.0.70.jar'
             )
 
             ws_jars = glob.glob(
-                option.current_dir + '/build/websocket-api-java-*.jar'
+                f'{option.current_dir}/build/websocket-api-java-*.jar'
             )
 
             if not ws_jars:
@@ -74,12 +74,12 @@ class TestApplicationJava(TestApplicationProto):
                 '-d',
                 classes_path,
                 '-classpath',
-                classpath + ':' + ws_jars[0],
+                f'{classpath}:{ws_jars[0]}',
             ]
             javac.extend(src)
 
             if option.detailed:
-                print("\n$ " + " ".join(javac))
+                print(f'\n$ {" ".join(javac)}')
 
             try:
                 subprocess.check_output(javac, stderr=subprocess.STDOUT)
@@ -88,26 +88,24 @@ class TestApplicationJava(TestApplicationProto):
                 raise
 
             except subprocess.CalledProcessError:
-                pytest.fail('Can\'t run javac process.')
+                pytest.fail("Can't run javac process.")
 
     def load(self, script, **kwargs):
         self.prepare_env(script)
 
+        script_path = f'{option.test_dir}/java/{script}/'
         self._load_conf(
             {
-                "listeners": {"*:7080": {"pass": "applications/" + script}},
+                "listeners": {"*:7080": {"pass": f"applications/{script}"}},
                 "applications": {
                     script: {
-                        "unit_jars": option.current_dir + '/build',
+                        "unit_jars": f'{option.current_dir}/build',
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
-                        "working_directory": option.test_dir
-                        + '/java/'
-                        + script
-                        + '/',
-                        "webapp": option.temp_dir + '/java',
+                        "working_directory": script_path,
+                        "webapp": f'{option.temp_dir}/java',
                     }
                 },
             },
-            **kwargs
+            **kwargs,
         )

test/unit/applications/lang/node.py

@@ -13,16 +13,16 @@ class TestApplicationNode(TestApplicationProto):
     def prepare_env(self, script):
         # copy application
         shutil.copytree(
-            option.test_dir + '/node/' + script, option.temp_dir + '/node'
+            f'{option.test_dir}/node/{script}', f'{option.temp_dir}/node'
         )
 
         # copy modules
         shutil.copytree(
-            option.current_dir + '/node/node_modules',
-            option.temp_dir + '/node/node_modules',
+            f'{option.current_dir}/node/node_modules',
+            f'{option.temp_dir}/node/node_modules',
         )
 
-        public_dir(option.temp_dir + '/node')
+        public_dir(f'{option.temp_dir}/node')
 
     def load(self, script, name='app.js', **kwargs):
         self.prepare_env(script)
@@ -43,17 +43,17 @@ class TestApplicationNode(TestApplicationProto):
         self._load_conf(
             {
                 "listeners": {
-                    "*:7080": {"pass": "applications/" + quote(script, '')}
+                    "*:7080": {"pass": f"applications/{quote(script, '')}"}
                 },
                 "applications": {
                     script: {
                         "type": "external",
                         "processes": {"spare": 0},
-                        "working_directory": option.temp_dir + '/node',
+                        "working_directory": f'{option.temp_dir}/node',
                         "executable": '/usr/bin/env',
                         "arguments": arguments,
                     }
                 },
             },
-            **kwargs
+            **kwargs,
         )

test/unit/applications/lang/perl.py

@@ -6,19 +6,19 @@ class TestApplicationPerl(TestApplicationProto):
     application_type = "perl"
 
     def load(self, script, name='psgi.pl', **kwargs):
-        script_path = option.test_dir + '/perl/' + script
+        script_path = f'{option.test_dir}/perl/{script}'
 
         self._load_conf(
             {
-                "listeners": {"*:7080": {"pass": "applications/" + script}},
+                "listeners": {"*:7080": {"pass": f"applications/{script}"}},
                 "applications": {
                     script: {
                         "type": self.get_application_type(),
                         "processes": {"spare": 0},
                         "working_directory": script_path,
-                        "script": script_path + '/' + name,
+                        "script": f'{script_path}/{name}',
                     }
                 },
             },
-            **kwargs
+            **kwargs,
         )

test/unit/applications/lang/php.py

@@ -9,18 +9,18 @@ class TestApplicationPHP(TestApplicationProto):
     application_type = "php"
 
     def load(self, script, index='index.php', **kwargs):
-        script_path = option.test_dir + '/php/' + script
+        script_path = f'{option.test_dir}/php/{script}'
 
         if kwargs.get('isolation') and kwargs['isolation'].get('rootfs'):
             rootfs = kwargs['isolation']['rootfs']
 
-            if not os.path.exists(rootfs + '/app/php/'):
-                os.makedirs(rootfs + '/app/php/')
+            if not os.path.exists(f'{rootfs}/app/php/'):
+                os.makedirs(f'{rootfs}/app/php/')
 
-            if not os.path.exists(rootfs + '/app/php/' + script):
-                shutil.copytree(script_path, rootfs + '/app/php/' + script)
+            if not os.path.exists(f'{rootfs}/app/php/{script}'):
+                shutil.copytree(script_path, f'{rootfs}/app/php/{script}')
 
-            script_path = '/app/php/' + script
+            script_path = f'/app/php/{script}'
 
         app = {
             "type": self.get_application_type(),
@@ -41,8 +41,8 @@ class TestApplicationPHP(TestApplicationProto):
 
         self._load_conf(
             {
-                "listeners": {"*:7080": {"pass": "applications/" + script}},
+                "listeners": {"*:7080": {"pass": f"applications/{script}"}},
                 "applications": {script: app},
             },
-            **kwargs
+            **kwargs,
         )

test/unit/applications/lang/python.py

@@ -20,18 +20,18 @@ class TestApplicationPython(TestApplicationProto):
         if script[0] == '/':
             script_path = script
         else:
-            script_path = option.test_dir + '/python/' + script
+            script_path = f'{option.test_dir}/python/{script}'
 
         if kwargs.get('isolation') and kwargs['isolation'].get('rootfs'):
             rootfs = kwargs['isolation']['rootfs']
 
-            if not os.path.exists(rootfs + '/app/python/'):
-                os.makedirs(rootfs + '/app/python/')
+            if not os.path.exists(f'{rootfs}/app/python/'):
+                os.makedirs(f'{rootfs}/app/python/')
 
-            if not os.path.exists(rootfs + '/app/python/' + name):
-                shutil.copytree(script_path, rootfs + '/app/python/' + name)
+            if not os.path.exists(f'{rootfs}/app/python/{name}'):
+                shutil.copytree(script_path, f'{rootfs}/app/python/{name}')
 
-            script_path = '/app/python/' + name
+            script_path = f'/app/python/{name}'
 
         app = {
             "type": self.get_application_type(),
@@ -58,9 +58,9 @@ class TestApplicationPython(TestApplicationProto):
         self._load_conf(
             {
                 "listeners": {
-                    "*:7080": {"pass": "applications/" + quote(name, '')}
+                    "*:7080": {"pass": f"applications/{quote(name, '')}"}
                 },
                 "applications": {name: app},
             },
-            **kwargs
+            **kwargs,
         )

test/unit/applications/lang/ruby.py

@@ -10,22 +10,22 @@ class TestApplicationRuby(TestApplicationProto):
 
     def prepare_env(self, script):
         shutil.copytree(
-            option.test_dir + '/ruby/' + script,
-            option.temp_dir + '/ruby/' + script,
+            f'{option.test_dir}/ruby/{script}',
+            f'{option.temp_dir}/ruby/{script}',
         )
 
-        public_dir(option.temp_dir + '/ruby/' + script)
+        public_dir(f'{option.temp_dir}/ruby/{script}')
 
     def load(self, script, name='config.ru', **kwargs):
         self.prepare_env(script)
 
-        script_path = option.temp_dir + '/ruby/' + script
+        script_path = f'{option.temp_dir}/ruby/{script}'
 
         app = {
             "type": self.get_application_type(),
             "processes": {"spare": 0},
             "working_directory": script_path,
-            "script": script_path + '/' + name,
+            "script": f'{script_path}/{name}',
         }
 
         for key in [
@@ -36,8 +36,8 @@ class TestApplicationRuby(TestApplicationProto):
 
         self._load_conf(
             {
-                "listeners": {"*:7080": {"pass": "applications/" + script}},
+                "listeners": {"*:7080": {"pass": f"applications/{script}"}},
                 "applications": {script: app},
             },
-            **kwargs
+            **kwargs,
         )

test/unit/applications/tls.py

@@ -22,13 +22,13 @@ class TestApplicationTLS(TestApplicationProto):
                 '-x509',
                 '-new',
                 '-subj',
-                '/CN=' + name + '/',
+                f'/CN={name}/',
                 '-config',
-                option.temp_dir + '/openssl.conf',
+                f'{option.temp_dir}/openssl.conf',
                 '-out',
-                option.temp_dir + '/' + name + '.crt',
+                f'{option.temp_dir}/{name}.crt',
                 '-keyout',
-                option.temp_dir + '/' + name + '.key',
+                f'{option.temp_dir}/{name}.key',
             ],
             stderr=subprocess.STDOUT,
         )
@@ -40,11 +40,11 @@ class TestApplicationTLS(TestApplicationProto):
         if key is None:
             key = crt
 
-        key_path = option.temp_dir + '/' + key + '.key'
-        crt_path = option.temp_dir + '/' + crt + '.crt'
+        key_path = f'{option.temp_dir}/{key}.key'
+        crt_path = f'{option.temp_dir}/{crt}.crt'
 
         with open(key_path, 'rb') as k, open(crt_path, 'rb') as c:
-            return self.conf(k.read() + c.read(), '/certificates/' + crt)
+            return self.conf(k.read() + c.read(), f'/certificates/{crt}')
 
     def get_ssl(self, **kwargs):
         return self.get(wrapper=self.context.wrap_socket, **kwargs)
@@ -54,54 +54,48 @@ class TestApplicationTLS(TestApplicationProto):
 
     def openssl_conf(self, rewrite=False, alt_names=None):
         alt_names = alt_names or []
-
-        conf_path = option.temp_dir + '/openssl.conf'
+        conf_path = f'{option.temp_dir}/openssl.conf'
 
         if not rewrite and os.path.exists(conf_path):
             return
 
         # Generates alt_names section with dns names
-        a_names = "[alt_names]\n"
+        a_names = '[alt_names]\n'
         for i, k in enumerate(alt_names, 1):
             k = k.split('|')
 
             if k[0] == 'IP':
-                a_names += "IP.%d = %s\n" % (i, k[1])
+                a_names += f'IP.{i} = {k[1]}\n'
             else:
-                a_names += "DNS.%d = %s\n" % (i, k[0])
+                a_names += f'DNS.{i} = {k[0]}\n'
 
         # Generates section for sign request extension
-        a_sec = """req_extensions = myca_req_extensions
+        a_sec = f'''req_extensions = myca_req_extensions
 
 [ myca_req_extensions ]
 subjectAltName = @alt_names
 
-{a_names}""".format(
-            a_names=a_names
-        )
+{a_names}'''
 
         with open(conf_path, 'w') as f:
             f.write(
-                """[ req ]
+                f'''[ req ]
 default_bits = 2048
 encrypt_key = no
 distinguished_name = req_distinguished_name
 
-{a_sec}
-[ req_distinguished_name ]""".format(
-                    a_sec=a_sec if alt_names else ""
-                )
+{a_sec if alt_names else ""}
+[ req_distinguished_name ]'''
             )
 
     def load(self, script, name=None):
         if name is None:
             name = script
 
-        script_path = option.test_dir + '/python/' + script
-
+        script_path = f'{option.test_dir}/python/{script}'
         self._load_conf(
             {
-                "listeners": {"*:7080": {"pass": "applications/" + name}},
+                "listeners": {"*:7080": {"pass": f"applications/{name}"}},
                 "applications": {
                     name: {
                         "type": "python",

test/unit/applications/websockets.py

@@ -52,7 +52,7 @@ class TestApplicationWebsocket(TestApplicationProto):
         while True:
             rlist = select.select([sock], [], [], 60)[0]
             if not rlist:
-                pytest.fail('Can\'t read response from server.')
+                pytest.fail("Can't read response from server.")
 
             resp += sock.recv(4096).decode()
 
@@ -77,7 +77,7 @@ class TestApplicationWebsocket(TestApplicationProto):
                     # For all current cases if the "read_timeout" was changed
                     # than test do not expect to get a response from server.
                     if read_timeout == 60:
-                        pytest.fail('Can\'t read response from server.')
+                        pytest.fail("Can't read response from server.")
                     break
 
                 data += sock.recv(bytes - len(data))

test/unit/check/chroot.py

@@ -12,7 +12,7 @@ def check_chroot():
     resp = http.put(
         url='/config',
         sock_type='unix',
-        addr=option.temp_dir + '/control.unit.sock',
+        addr=f'{option.temp_dir}/control.unit.sock',
         body=json.dumps(
             {
                 "listeners": {"*:7080": {"pass": "routes"}},

test/unit/check/isolation.py

@@ -27,8 +27,8 @@ def check_isolation():
                 "empty": {
                     "type": "external",
                     "processes": {"spare": 0},
-                    "working_directory": option.test_dir + "/go/empty",
-                    "executable": option.temp_dir + "/go/app",
+                    "working_directory": f"{option.test_dir}/go/empty",
+                    "executable": f"{option.test_dir}/go/app",
                     "isolation": {"namespaces": {"credential": True}},
                 },
             },
@@ -41,8 +41,8 @@ def check_isolation():
                 "empty": {
                     "type": "python",
                     "processes": {"spare": 0},
-                    "path": option.test_dir + "/python/empty",
-                    "working_directory": option.test_dir + "/python/empty",
+                    "path": f"{option.test_dir}/python/empty",
+                    "working_directory": f"{option.test_dir}/python/empty",
                     "module": "wsgi",
                     "isolation": {"namespaces": {"credential": True}},
                 }
@@ -56,8 +56,8 @@ def check_isolation():
                 "phpinfo": {
                     "type": "php",
                     "processes": {"spare": 0},
-                    "root": option.test_dir + "/php/phpinfo",
-                    "working_directory": option.test_dir + "/php/phpinfo",
+                    "root": f"{option.test_dir}/php/phpinfo",
+                    "working_directory": f"{option.test_dir}/php/phpinfo",
                     "index": "index.php",
                     "isolation": {"namespaces": {"credential": True}},
                 }
@@ -73,8 +73,8 @@ def check_isolation():
                 "empty": {
                     "type": "ruby",
                     "processes": {"spare": 0},
-                    "working_directory": option.temp_dir + "/ruby/empty",
-                    "script": option.temp_dir + "/ruby/empty/config.ru",
+                    "working_directory": f"{option.temp_dir}/ruby/empty",
+                    "script": f"{option.temp_dir}/ruby/empty/config.ru",
                     "isolation": {"namespaces": {"credential": True}},
                 }
             },
@@ -87,11 +87,11 @@ def check_isolation():
             "listeners": {"*:7080": {"pass": "applications/empty"}},
             "applications": {
                 "empty": {
-                    "unit_jars": option.current_dir + "/build",
+                    "unit_jars": f"{option.current_dir}/build",
                     "type": "java",
                     "processes": {"spare": 0},
-                    "working_directory": option.test_dir + "/java/empty/",
-                    "webapp": option.temp_dir + "/java",
+                    "working_directory": f"{option.temp_dir}/java/empty/",
+                    "webapp": f"{option.temp_dir}/java",
                     "isolation": {"namespaces": {"credential": True}},
                 }
             },
@@ -106,7 +106,7 @@ def check_isolation():
                 "basic": {
                     "type": "external",
                     "processes": {"spare": 0},
-                    "working_directory": option.temp_dir + "/node",
+                    "working_directory": f"{option.temp_dir}/node",
                     "executable": "app.js",
                     "isolation": {"namespaces": {"credential": True}},
                 }
@@ -120,8 +120,8 @@ def check_isolation():
                 "body_empty": {
                     "type": "perl",
                     "processes": {"spare": 0},
-                    "working_directory": option.test_dir + "/perl/body_empty",
-                    "script": option.test_dir + "/perl/body_empty/psgi.pl",
+                    "working_directory": f"{option.test_dir}/perl/body_empty",
+                    "script": f"{option.test_dir}/perl/body_empty/psgi.pl",
                     "isolation": {"namespaces": {"credential": True}},
                 }
             },
@@ -133,7 +133,7 @@ def check_isolation():
     resp = http.put(
         url='/config',
         sock_type='unix',
-        addr=option.temp_dir + '/control.unit.sock',
+        addr=f'{option.temp_dir}/control.unit.sock',
         body=json.dumps(conf),
     )
 

test/unit/check/node.py

@@ -3,7 +3,7 @@ import subprocess
 
 
 def check_node(current_dir):
-    if not os.path.exists(current_dir + '/node/node_modules'):
+    if not os.path.exists(f'{current_dir}/node/node_modules'):
         return None
 
     try:

test/unit/check/unix_abstract.py

@@ -12,7 +12,7 @@ def check_unix_abstract():
     resp = http.put(
         url='/config',
         sock_type='unix',
-        addr=option.temp_dir + '/control.unit.sock',
+        addr=f'{option.temp_dir}/control.unit.sock',
         body=json.dumps(
             {
                 "listeners": {"unix:@sock": {"pass": "routes"}},

test/unit/control.py

@@ -21,7 +21,7 @@ def args_handler(conf_func):
 
             url = args[1] if len(args) == 2 else url_default
 
-        url = url if url.startswith('/') else url_default + '/' + url
+        url = url if url.startswith('/') else f'{url_default}/{url}'
         arguments = (self, url) if conf is None else (self, conf, url)
 
         return json.loads(conf_func(*arguments))
@@ -50,7 +50,7 @@ class TestControl(TestHTTP):
         args = {
             'url': url,
             'sock_type': 'unix',
-            'addr': option.temp_dir + '/control.unit.sock',
+            'addr': f'{option.temp_dir}/control.unit.sock',
         }
 
         if conf is not None:

test/unit/http.py

@@ -53,13 +53,13 @@ class TestHTTP:
                 sock.connect(connect_args)
             except (ConnectionRefusedError, FileNotFoundError):
                 sock.close()
-                pytest.fail('Client can\'t connect to the server.')
+                pytest.fail("Client can't connect to the server.")
 
         else:
             sock = kwargs['sock']
 
         if 'raw' not in kwargs:
-            req = ' '.join([start_str, url, http]) + crlf
+            req = f'{start_str} {url} {http}{crlf}'
 
             if body != b'':
                 if isinstance(body, str):
@@ -75,10 +75,10 @@ class TestHTTP:
             for header, value in headers.items():
                 if isinstance(value, list):
                     for v in value:
-                        req += header + ': ' + str(v) + crlf
+                        req += f'{header}: {v}{crlf}'
 
                 else:
-                    req += header + ': ' + str(value) + crlf
+                    req += f'{header}: {value}{crlf}'
 
             req = (req + crlf).encode() + body
 
@@ -151,12 +151,12 @@ class TestHTTP:
         len_log = len(log)
         if len_log > limit:
             log = log[:limit]
-            appendix = '(...logged %s of %s bytes)' % (limit, len_log)
+            appendix = f'(...logged {limit} of {len_log} bytes)'
 
             if isinstance(log, bytes):
                 appendix = appendix.encode()
 
-            log = log + appendix
+            log = f'{log}{appendix}'
 
         return log
 
@@ -188,7 +188,7 @@ class TestHTTP:
                 # For all current cases if the "read_timeout" was changed
                 # than test do not expect to get a response from server.
                 if timeout == timeout_default:
-                    pytest.fail('Can\'t read response from server.')
+                    pytest.fail("Can't read response from server.")
                 break
 
             try:
@@ -263,7 +263,7 @@ class TestHTTP:
                 size = int(chunks.pop(0), 16)
 
             except ValueError:
-                pytest.fail('Invalid chunk size %s' % str(size))
+                pytest.fail(f'Invalid chunk size {size}')
 
             if size == 0:
                 assert len(chunks) == 1, 'last zero size'
@@ -310,7 +310,7 @@ class TestHTTP:
 
     def form_url_encode(self, fields):
         data = "&".join(
-            "%s=%s" % (name, value) for name, value in fields.items()
+            f'{name}={value}' for name, value in fields.items()
         ).encode()
         return data, 'application/x-www-form-urlencoded'
 
@@ -341,21 +341,21 @@ class TestHTTP:
             else:
                 pytest.fail('multipart requires a string or stream data')
 
-            body += ("--%s\r\nContent-Disposition: form-data; name=\"%s\"") % (
-                boundary,
-                field,
+            body += (
+                f'--{boundary}\r\nContent-Disposition: form-data;'
+                f'name="{field}"'
             )
 
             if filename != '':
-                body += "; filename=\"%s\"" % filename
+                body += f'; filename="{filename}"'
 
-            body += "\r\n"
+            body += '\r\n'
 
             if datatype != '':
-                body += "Content-Type: %s\r\n" % datatype
+                body += f'Content-Type: {datatype}\r\n'
 
-            body += "\r\n%s\r\n" % data
+            body += f'\r\n{data}\r\n'
 
-        body += "--%s--\r\n" % boundary
+        body += f'--{boundary}--\r\n'
 
-        return body.encode(), "multipart/form-data; boundary=%s" % boundary
+        return body.encode(), f'multipart/form-data; boundary={boundary}'

test/unit/log.py

@@ -20,4 +20,4 @@ class Log:
         Log.pos[name] = pos
 
     def get_path(name=UNIT_LOG):
-        return Log.temp_dir + '/' + name
+        return f'{Log.temp_dir}/{name}'

test/unit/utils.py

@@ -69,7 +69,7 @@ def waitforsocket(port):
             except KeyboardInterrupt:
                 raise
 
-    pytest.fail('Can\'t connect to the 127.0.0.1:' + str(port))
+    pytest.fail(f"Can't connect to the 127.0.0.1:{port}")
 
 
 def check_findmnt():
@@ -125,7 +125,7 @@ def getns(nstype):
     # read namespace id from symlink file:
     # it points to: '<nstype>:[<ns id>]'
     # # eg.: 'pid:[4026531836]'
-    nspath = '/proc/self/ns/' + nstype
+    nspath = f'/proc/self/ns/{nstype}'
     data = None
 
     if os.path.exists(nspath):