Tests: get rid of classes in test files.

Class usage came from the unittest framework and it was always redundant
after migration to the pytest.  This commit removes classes from files
containing tests to make them more readable and understandable.

test/test_reconfigure.py

@@ -1,50 +1,54 @@
 import time
 
 import pytest
-from unit.applications.proto import TestApplicationProto
+from unit.applications.proto import ApplicationProto
+
+client = ApplicationProto()
 
 
-class TestReconfigure(TestApplicationProto):
-    @pytest.fixture(autouse=True)
-    def setup_method_fixture(self):
-        assert 'success' in self.conf(
-            {
-                "listeners": {"*:7080": {"pass": "routes"}},
-                "routes": [{"action": {"return": 200}}],
-                "applications": {},
-            }
-        )
+@pytest.fixture(autouse=True)
+def setup_method_fixture():
+    assert 'success' in client.conf(
+        {
+            "listeners": {"*:7080": {"pass": "routes"}},
+            "routes": [{"action": {"return": 200}}],
+            "applications": {},
+        }
+    )
 
-    def clear_conf(self):
-        assert 'success' in self.conf({"listeners": {}, "applications": {}})
 
-    def test_reconfigure(self):
-        sock = self.http(
-            b"""GET / HTTP/1.1
+def clear_conf():
+    assert 'success' in client.conf({"listeners": {}, "applications": {}})
+
+
+def test_reconfigure():
+    sock = client.http(
+        b"""GET / HTTP/1.1
 """,
-            raw=True,
-            no_recv=True,
-        )
+        raw=True,
+        no_recv=True,
+    )
 
-        self.clear_conf()
+    clear_conf()
 
-        resp = self.http(
-            b"""Host: localhost
+    resp = client.http(
+        b"""Host: localhost
 Connection: close
 
 """,
-            sock=sock,
-            raw=True,
-        )
-        assert resp['status'] == 200, 'finish request'
+        sock=sock,
+        raw=True,
+    )
+    assert resp['status'] == 200, 'finish request'
 
-    def test_reconfigure_2(self):
-        sock = self.http(b'', raw=True, no_recv=True)
 
-        # Waiting for connection completion.
-        # Delay should be more than TCP_DEFER_ACCEPT.
-        time.sleep(1.5)
+def test_reconfigure_2():
+    sock = client.http(b'', raw=True, no_recv=True)
 
-        self.clear_conf()
+    # Waiting for connection completion.
+    # Delay should be more than TCP_DEFER_ACCEPT.
+    time.sleep(1.5)
 
-        assert self.get(sock=sock)['status'] == 408, 'request timeout'
+    clear_conf()
+
+    assert client.get(sock=sock)['status'] == 408, 'request timeout'