fastify.inject like testing for WS?

[gjovanov]

Hey guys,
for faking HTTP requests, there is ab option to inject fake HTTP requests via light-my-request. Looking in the tests of this repo, I can see that Fastify really needs to listen on some port in order to create a WS client connetion.

Is there a way to Inject a WS connection without actually making Fastify server listen on a port?

I'm asking because right now we many HTTP tests using Ava testing framework, that are in many separate files (due to concurrent testing). So far for HTTP testing we were not forcing the Fastify server to listen on any port. Now we are at the point where we want to start cover the WS scenarios with such tests and it seems that we are going to need to actually make Fastify server listen on certain port.

The issue we are seeing is that each test file will need to have a separate port, because they run concurrently. I know it's doable like that, but I'm just currious if it's possible to fake WS connections as well as WS data being sent?

Thanks in advance.

/GJ

[mcollina]

That would be a fantastic feature! Would you like to send a PR? The way I would build this is to use https://github.com/mafintosh/duplexify to create a couple of "inverted" duplex streams from a couple of PassThrough. Then, we can issue an 'upgrade' event on the server.
Wdyt? Would you like to send a PR?

[gjovanov]

Hey @mcollina, indeed it would be a useful feature.

So far I haven't had a look in the source code of Fastify, so I decided to have a look in both Fastify and Duplexify, to evaluate a potential contribution via a PR. At first glance this seems too overwhelming, considering other tasks on my plate.

Maybe if you help me out providing some hints where to start looking in the source code options for checking PassThrough requests and issuing events on the server? Also what would be the flow of establishing a WS? E.g. PassThrough request with A, B, C headers etc, then Upgrade request with X, Y, Z headers?

[mcollina]

Essentially you'll need to add a decorator that calls https://github.com/fastify/fastify-websocket/blob/master/index.js#L63-L67 with the right arguments.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[airhorns]

There's also the mock-socket library here (https://github.com/thoov/mock-socket), which I've had good success with. If we made the server implementation an option, you could maybe just inject the mock server and use the mock socket client which quacks more like a normal WebSocket and handles all the internal event emission for you.

[mcollina]

That'd work! Would you like to send a PR?

[wyozi]

Ideally, I'd be very happy with something like

const ws = fastify.injectWebSocket('/my/ws/path')
ws.send('hello world') // just a normal WS instance

without having to touch the original plugin options at all.

I don't think this would be doable with the ws library though, except maybe hacking with passing a null address to the WS client somehow to make it operate in server mode?

[mcollina]

I have not designed this :(. It probably requires some analysis and experimentation.