tests: socket_comms: test broadcast without clients

Ensure that the local server can broadcast to the multicast group even
if there are no clients connected. This ensures the gateway doesn't
crash before any client tools are connected.

Signed-off-by: Jordan Yates <jordan@embeint.com>

Author: JordanYates

tests/test_socket_comms.py

@@ -12,8 +12,17 @@ def test_socket_comms():
     multicast_addr = comms.default_multicast_address()
     # Increment port by 1 so we can run the tests in parallel with a real instance
     test_addr = (multicast_addr[0], multicast_addr[1] + 1)
+
+    # Create the server first
     server = comms.LocalServer(test_addr)
+
+    # Send a message before any client is connected
+    broadcast_msg = comms.ClientNotificationObservedDevices({})
+    server.broadcast(broadcast_msg)
+
+    # Create a client that receives from the server, shouldn't receive the broadcast message
     client = comms.LocalClient(test_addr)
+    assert client.receive() is None
 
     # Send request to server
     request = comms.GatewayRequestCommsCheck()