Add pub-sub test using WebSockets (disabled)

Add new pub-sub test using WebSockets, disabled by default due to
message ordering not matching what is expected.
Enable the test with `PUBSUB=1 ./ws-tests.py`

tests/ws-tests.py

@@ -92,5 +92,75 @@ class TestRaw(TestWebdis):
 		self.assertEqual(get_response, f"${len(value)}\r\n{value}\r\n")
 
 
+@unittest.skipIf(os.getenv('PUBSUB') != '1', "pub-sub test fail due to invalid ordering")
+class TestPubSub(unittest.TestCase):
+	def setUp(self):
+		self.publisher = create_connection(f'ws://{host}:{port}/.json')
+		self.subscriber = create_connection(f'ws://{host}:{port}/.json')
+
+	def tearDown(self):
+		self.publisher.close()
+		self.subscriber.close()
+
+	def serialize(self, cmd, *args):
+		return json.dumps([cmd] + list(args))
+
+	def deserialize(self, response):
+		return json.loads(response)
+
+	def test_publish_subscribe(self):
+		channel_count = 2
+		message_count_per_channel = 8
+		channels = list(str(uuid.uuid4()) for i in range(channel_count))
+
+		# subscribe to all channels
+		sub_count = 0
+		for channel in channels:
+			self.subscriber.send(self.serialize('SUBSCRIBE', channel))
+			unsub_response = self.deserialize(self.subscriber.recv())
+			sub_count += 1
+			self.assertEqual(unsub_response, {'SUBSCRIBE': ['subscribe', channel, sub_count]})
+
+		# send messages to all channels
+		prefix = 'message-'
+		for i in range(message_count_per_channel):
+			for channel in channels:
+				message = f'{prefix}{i}'
+				self.publisher.send(self.serialize('PUBLISH', channel, message))
+
+		received_per_channel = dict((channel, []) for channel in channels)
+		for j in range(channel_count * message_count_per_channel):
+			received = self.deserialize(self.subscriber.recv())
+			print('received:', received)
+			# expected: {'SUBSCRIBE': ['message', $channel, $message]}
+			self.assertTrue(received, 'SUBSCRIBE' in received)
+			sub_contents = received['SUBSCRIBE']
+			self.assertEqual(len(sub_contents), 3)
+
+			self.assertEqual(sub_contents[0], 'message')  # first element is the message type, here a push
+			channel = sub_contents[1]
+			self.assertTrue(channel in channels)  # second is the channel
+			received_per_channel[channel].append(sub_contents[2])  # third, add to list of messages received for this channel
+
+		# unsubscribe from all channels
+		subs_remaining = channel_count
+		for channel in channels:
+			self.subscriber.send(self.serialize('UNSUBSCRIBE', channel))
+			subs_remaining -= 1
+			unsub_response = self.deserialize(self.subscriber.recv())
+			self.assertEqual(unsub_response, {'SUBSCRIBE': ['unsubscribe', channel, subs_remaining]})
+
+		# check that we received all messages
+		for channel in channels:
+			self.assertEqual(len(received_per_channel[channel]), message_count_per_channel)
+
+		# check that we received them *in order*
+		for i in range(message_count_per_channel):
+			for channel in channels:
+				expected = f'{prefix}{i}'
+				self.assertEqual(received_per_channel[channel][i], expected,
+					f'In {channel}: expected at offset {i} was "{expected}", actual was: "{received_per_channel[channel][i]}"')
+
+
 if __name__ == '__main__':
 	unittest.main()