Add testing methods/examples about flask-socketio

[TronPaul]

If I can get something working that looks like my sample code I'll make a pull request. If anyone has any other ideas for how to accomplish this, I'd love to see them.

[miguelgrinberg]

I was thinking that for unit tests I was going to start the app for real and use a websocket client to acccess it. There is client that looks decent: https://pypi.python.org/pypi/websocket-client/, but I haven't tried it yet.

[TronPaul]

I didn't really want to do end to end testing at this stage. And you can set the test_client_class in flask. I think I should be able to extend FlaskClient (flask's test client) to behave as expected for websockets. Would something of that nature be good for a pull request?

[miguelgrinberg]

Oh sure, if you manage to get testing going I would take it.

I'm not sure you need a connection to the test client, though, since the socket stuff runs independently. You could have a SocketIOTestClient class for example that can send and receive socket.io messages.

The send() and emit() methods in this client would just invoke recv_message(), recv_json() or process_event() in the SocketIO object.

Receiving events from the server is going to be a little bit more tricky, you will need to get the GenericNamespace objects to inherit from a class that is compatible with BaseNamespace from gevent-socketio, but that instead of routing messages through the real thing it makes the messages available to the test client.

[TronPaul]

Well the socket stuff runs independently, but there's a few things on the behavior of the context globals (with respect to their modifications with Flask-SocketIO) in flask that I'd like to test. I'd imagine that it'd be easier to tie it in with an additional mixin to the FlaskClient, but just having a test_client on the socketio might be simpler and fit my use case. I'll see how this goes.

[miguelgrinberg]

Ah, but the context globals are all handled SocketIO.dispatch_message(), which is invoked by recv_message(), recv_json() and process_event(), so I think if you follow my advice you are covered on that front.

[miguelgrinberg]

I believe the need for unit tests is now addressed. Closing.