test: add test for socket server returning 409

tests/slack_sdk/socket_mode/mock_socket_mode_server.py

@@ -159,3 +159,37 @@ def run_server():
         loop.close()
 
     return run_server
+
+def start_bad_socket_mode_server(self, port: int):
+    logger = logging.getLogger(__name__)
+    state = {}
+
+    def reset_server_state():
+        self.state = {}
+
+    self.reset_server_state = reset_server_state
+
+    async def link(request):
+        return web.Response(status=409)
+
+    app = web.Application()
+    app.add_routes([web.get("/link", link)])
+    runner = web.AppRunner(app)
+
+    def run_server():
+        reset_server_state()
+
+        self.loop = loop = asyncio.new_event_loop()
+        asyncio.set_event_loop(loop)
+        loop.run_until_complete(runner.setup())
+        site = web.TCPSite(runner, "127.0.0.1", port, reuse_port=True)
+        loop.run_until_complete(site.start())
+
+        # run until it's stopped from the main thread
+        loop.run_forever()
+
+        loop.run_until_complete(runner.cleanup())
+        loop.run_until_complete(asyncio.sleep(1))
+        loop.close()
+
+    return run_server

tests/slack_sdk/socket_mode/test_interactions_websocket_client.py

@@ -14,6 +14,7 @@
 from slack_sdk.socket_mode.websocket_client import SocketModeClient
 from tests.helpers import is_ci_unstable_test_skip_enabled
 from tests.slack_sdk.socket_mode.mock_socket_mode_server import (
+    start_bad_socket_mode_server,
     start_socket_mode_server,
     socket_mode_envelopes,
     socket_mode_hello_message,
@@ -133,3 +134,28 @@ def test_send_message_while_disconnection(self):
             client.close()
             self.loop.stop()
             t.join(timeout=5)
+
+    def test_wss_craps_itself(self):
+        if is_ci_unstable_test_skip_enabled():
+            # this test tends to fail on the GitHub Actions platform
+            return
+        t = Thread(target=start_bad_socket_mode_server(self, 3012))
+        t.daemon = True
+        t.start()
+        time.sleep(2)  # wait for the server
+
+        try:
+            client = SocketModeClient(
+                app_token="xapp-A111-222-xyz",
+                web_client=self.web_client,
+                auto_reconnect_enabled=False,
+                trace_enabled=True,
+            )
+            client.wss_uri = "ws://0.0.0.0:3012/link"
+            client.connect()
+            time.sleep(1)  # wait for the connection
+            assert client.is_connected() is True
+        finally:
+            client.close()
+            self.loop.stop()
+            t.join(timeout=5)