Can something like “Rule” be used in kotest? I need to set the MainCoroutineRule.

# kotest

[Luis Daivid]

Can something like “Rule” be used in kotest? I need to set the MainCoroutineRule.

[sam]

junit rule ?

[Luis Daivid]

YES

[sam]

no, they're for junit, but you might not need it. What does main coroutine rule do ?

[Luis Daivid]

@ExperimentalCoroutinesApi
class MainCoroutineRule(
    val testDispatcher: TestCoroutineDispatcher = TestCoroutineDispatcher()
) : TestWatcher() {

    override fun starting(description: Description?) {
        super.starting(description)
        Dispatchers.setMain(testDispatcher)
    }

    override fun finished(description: Description?) {
        super.finished(description)
        Dispatchers.resetMain()
        testDispatcher.cleanupTestCoroutines()
    }
}

[Luis Daivid]

I am trying to apply kotest to Android.

[sam]

In kotest, all tests are coroutines, so you can just use withContext and set any dispatcher you want

[sam]

test("my test") {
  withContext(TestCoroutineDispatcher()) {
    ...
  }
}

[sam]

or if that doesn't work (I'm not sure what Dispatchers.setMain is), you could write a listener to do that easily

[sam]

class MainCoroutineListener(
    val testDispatcher: TestCoroutineDispatcher = TestCoroutineDispatcher()
) : TestListener() {

    override fun beforeTest(description: Description?) {
        Dispatchers.setMain(testDispatcher)
    }

    override fun afterTest(description: Description?) {
        Dispatchers.resetMain()
        testDispatcher.cleanupTestCoroutines()
    }
}

[sam]

https://kotest.io/docs/framework/listeners.html

[Luis Daivid]

Is this how to create a new testListener?

[Luis Daivid]

Is it possible to create a custom listener?

[Luis Daivid]

Oh I see.

[Luis Daivid]

class MyTestClass : FunSpec({
listeners(TimerListener)
// tests here
})

[Luis Daivid]

class MyTestClass : FunSpec({
listeners(MainCoroutineListener)
// tests here
})

[sam]

yes

[sam]

exactly

[sam]

or if you want to register them at the global level, you can use project config

[Luis Daivid]

Thank you. You are really kind.

[sam]

https://kotest.io/docs/framework/project-config.html

[Luis Daivid]

Thank you. It was very helpful.