Add test/compatibility folder with small servers and clients written in different languages and different libraries to test compatibility.

test/compatibility/python/websockets/echo_server.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+
+# WS server example
+
+import asyncio
+import websockets
+
+async def hello(websocket, path):
+    await websocket.send(f"> Welcome !")
+
+    name = await websocket.recv()
+    print(f"< {name}")
+
+    greeting = f"Hello {name}!"
+
+    await websocket.send(greeting)
+    print(f"> {greeting}")
+
+start_server = websockets.serve(hello, 'localhost', 8765)
+
+asyncio.get_event_loop().run_until_complete(start_server)
+asyncio.get_event_loop().run_forever()