Python: supporting ASGI legacy protocol.

Introducing manual protocol selection for 'universal' apps and frameworks.

test/python/legacy/asgi.py

@@ -0,0 +1,13 @@
+def application(scope):
+    assert scope['type'] == 'http'
+
+    return app_http
+
+async def app_http(receive, send):
+    await send({
+        'type': 'http.response.start',
+        'status': 200,
+        'headers': [
+            (b'content-length', b'0'),
+        ]
+    })

test/python/legacy_force/asgi.py

@@ -0,0 +1,17 @@
+def application(scope, receive=None, send=None):
+    assert scope['type'] == 'http'
+
+    if receive == None and send == None:
+        return app_http
+
+    else:
+        return app_http(receive, send)
+
+async def app_http(receive, send):
+    await send({
+        'type': 'http.response.start',
+        'status': 200,
+        'headers': [
+            (b'content-length', b'0'),
+        ]
+    })

test/test_asgi_application.py

@@ -418,3 +418,29 @@ Connection: close
             sock.close()
 
         assert len(socks) == len(threads), 'threads differs'
+
+    def test_asgi_application_legacy(self):
+        self.load('legacy')
+
+        resp = self.get(
+            headers={
+                'Host': 'localhost',
+                'Content-Length': '0',
+                'Connection': 'close',
+            },
+        )
+
+        assert resp['status'] == 200, 'status'
+
+    def test_asgi_application_legacy_force(self):
+        self.load('legacy_force', protocol='asgi')
+
+        resp = self.get(
+            headers={
+                'Host': 'localhost',
+                'Content-Length': '0',
+                'Connection': 'close',
+            },
+        )
+
+        assert resp['status'] == 200, 'status'

test/unit/applications/lang/python.py

@@ -42,7 +42,8 @@ class TestApplicationPython(TestApplicationProto):
             "module": module,
         }
 
-        for attr in ('callable', 'home', 'limits', 'path', 'threads'):
+        for attr in ('callable', 'home', 'limits', 'path', 'protocol',
+                     'threads'):
             if attr in kwargs:
                 app[attr] = kwargs.pop(attr)