So, I am trying to write some tests for Flows using Turbine lib and I found myself in the need to as...

# coroutines

[juliocbcotta]

So, I am trying to write some tests for Flows using Turbine lib and I found myself in the need to assert some flow emissions that would be triggered after I call .test ... something like

val flow = MutableStateFlow(1)
    flow.test {
        assertEquals(awaitItem(), 1)
        assertEquals(awaitItem(), 2) // <-- waits forever
}
flow.emit(2)

Would anyone have a tip on how to properly test it ?

[Paul Woitaschek]

How would you expect this to work? You call the emit after you are waiting for the second item.
Call emit between the two awaitItems

[Paul Woitaschek]

It's like expecting the lights to go on before pressing the switch

[juliocbcotta]

I understand what is happening, I just don't know how to test it. I would like to listen to the emissions and make the emissions happen later in my test, that was just an example.

[juliocbcotta]

I would expect that turbine would make some "magic trick" inside the lambda to decouple the collection from the test.

[Paul Woitaschek]

The trick is not to run the lamba. Iirc there was a call that gives you the Turbine directly

[Paul Woitaschek]

Once the lambda returns, Turbine is done.
Depending on the use case just call your functions from within the lambda

[jw]

Move emit inside the lambda

[julian]

👆🏽https://github.com/cashapp/turbine#hot-flows

[juliocbcotta]

Thanks, I read the doc, but missed the point of emitting inside the lambda as being the way to test that kind of case.