dispatchers_unfinished.kt

interface IssueReporter {
    fun reportIssue(e: Exception)
}

interface SoundPlayer {
    suspend fun playSound()
}

class MediaPlayer(
    private val scope: CoroutineScope,
    private val soundPlayer: SoundPlayer,
    private val issueReporter: IssueReporter
) {

    val playerErrors = MutableSharedFlow<Exception>()

    init {
        scope.launch {
            playerErrors.collect {
                issueReporter.reportIssue(it)
            }
        }
    }

    fun play() {
        scope.launch {
            try {
                soundPlayer.playSound()
            } catch (e: Exception) {
                playerErrors.emit(e)
            }
        }
    }

}

@OptIn(ExperimentalCoroutinesApi::class)
class NeverEndingCoroutineTest {

    @Test
    fun `should emit error when playSound throws`() = runTest {

        val exception = Exception("Oopsie")
        val soundPlayer = mockk<SoundPlayer>()
        val issueReporter = mockk<IssueReporter>()
        justRun { issueReporter.reportIssue(any()) }
        coEvery { soundPlayer.playSound() } throws exception

        val sut = MediaPlayer(this, soundPlayer, issueReporter)

        sut.playerErrors.test {
            sut.play()
            awaitItem() shouldBe exception
        }

    }

}