broke websocket API and added tests

Author: flying-sheep

aiohttp/websocket.py

@@ -218,7 +218,7 @@ def do_handshake(method, headers, transport, protocols=()):
                 break
         else:
             raise errors.HttpBadRequest(
-                'Client protocols {} don’t overlap server-known ones {}'
+                'Client protocols {!r} don’t overlap server-known ones {!r}'
                 .format(protocols, req_protocols))
 
     # check supported version
@@ -246,8 +246,9 @@ def do_handshake(method, headers, transport, protocols=()):
     if protocol:
         response_headers.append(('SEC-WEBSOCKET-PROTOCOL', protocol))
 
-    # response code, headers, parser, writer
+    # response code, headers, parser, writer, protocol
     return (101,
             response_headers,
             WebSocketParser,
-            WebSocketWriter(transport))
+            WebSocketWriter(transport),
+            protocol)

tests/test_websocket.py

@@ -419,18 +419,54 @@ def test_protocol_key(self):
             websocket.do_handshake,
             self.message.method, self.message.headers, self.transport)
 
+    def gen_ws_headers(self, protocols=''):
+        key = base64.b64encode(os.urandom(16)).decode()
+        hdrs = [('UPGRADE', 'websocket'),
+                ('CONNECTION', 'upgrade'),
+                ('SEC-WEBSOCKET-VERSION', '13'),
+                ('SEC-WEBSOCKET-KEY', key)]
+        if protocols:
+            hdrs += [('SEC-WEBSOCKET-PROTOCOL', protocols)]
+        return hdrs, key
+
     def test_handshake(self):
-        sec_key = base64.b64encode(os.urandom(16)).decode()
+        hdrs, sec_key = self.gen_ws_headers()
 
-        self.headers.extend([('UPGRADE', 'websocket'),
-                             ('CONNECTION', 'upgrade'),
-                             ('SEC-WEBSOCKET-VERSION', '13'),
-                             ('SEC-WEBSOCKET-KEY', sec_key)])
-        status, headers, parser, writer = websocket.do_handshake(
+        self.headers.extend(hdrs)
+        status, headers, parser, writer, protocol = websocket.do_handshake(
             self.message.method, self.message.headers, self.transport)
         self.assertEqual(status, 101)
+        self.assertIsNone(protocol)
 
         key = base64.b64encode(
             hashlib.sha1(sec_key.encode() + websocket.WS_KEY).digest())
         headers = dict(headers)
         self.assertEqual(headers['SEC-WEBSOCKET-ACCEPT'], key.decode())
+
+    def test_handshake_protocol(self):
+        '''Tests if one protocol is returned by do_handshake'''
+        proto = 'chat'
+
+        self.headers.extend(self.gen_ws_headers(proto)[0])
+        _, resp_headers, _, _, protocol = websocket.do_handshake(
+            self.message.method, self.message.headers, self.transport,
+            protocols=[proto])
+
+        self.assertEqual(protocol, proto)
+
+        #also test if we reply with the protocol
+        resp_headers = dict(resp_headers)
+        self.assertEqual(resp_headers['SEC-WEBSOCKET-PROTOCOL'], proto)
+
+    def test_handshake_protocol_agreement(self):
+        '''Tests if the right protocol is selected given multiple'''
+        best_proto = 'chat'
+        wanted_protos = ['best', 'chat', 'worse_proto']
+        server_protos = 'worse_proto,chat'
+
+        self.headers.extend(self.gen_ws_headers(server_protos)[0])
+        _, resp_headers, _, _, protocol = websocket.do_handshake(
+            self.message.method, self.message.headers, self.transport,
+            protocols=wanted_protos)
+
+        self.assertEqual(protocol, best_proto)