WebSocket support for Mock engine

Subsystem Client (Mock engine), WebSocket

Is your feature request related to a problem? Please describe. Currently there is no WebSocket support for the Mock engine on the client part. This could be particularly useful when testing clients that interact with WebSockets.

Describe the solution you’d like I think there should be a method inside the Mock engine that allows to setup a proper WebSocket mock. This could be something like

private val client = HttpClient(MockEngine) {
    engine {
        addWebSocketHandler(host = "localhost", port = 8080, path = "/ws") { incoming, outgoing ->

        }
    }
}

Motivation to include to ktor This feature could be useful to all the people that want to test a client that interacts with a websocket without having to spin one up.

[shaunek]

@e5l This issue seems to be about websocket client testing, and you closed this issue out mentioning it is supported with the withTestApplication function… I could be missing something but withTestApplication seems to be pretty focused on the ktor server testing as it requires an Application.method to be provided. I looked and couldn’t find any client-only focused mock engines that support websockets. The current docs (v1.6) still recommend using MockEngine with HttpClient, but MockEngine doesn’t seem to support websockets as far as I can tell.

Are you aware of any client-only websocket testing library besides OkHTTP’s MockWebServer? If so can you please point me in the right direction? For context, I have JVM-hosted websocket client that needs to consume a third party service over websockets and I’m not finding helpful examples that are unit testable. I was hoping to find something that doesn’t require running a server to test the client code - something similar to ktor’s HttpClient+MockEngine that makes it possible to test client code without running a server.

If you aren’t aware of any libraries fitting my description I wonder if it could be helpful to reopen this issue?

[oleg-larshin]

Please check the following ticket on YouTrack for follow-ups to this issue. GitHub issues will be closed in the coming weeks.