Flow Unit testcase

FlowTests.kt

//models
data class RequestData(val data:String)
class BusinessException(val msg:String):Throwable(msg)

//Interactor
interface IDataRequestInteractor {
    suspend fun getData(): RequestData
}

// ViewModel
class MainViewModel @Inject constructor(
    private val interactor: IDataRequestInteractor,
) : ViewModel() {

    private val _loading = MutableStateFlow(true)
    val loading = _loading.asStateFlow()

    private val _data = MutableStateFlow("")
    val data = _data.asStateFlow()

    private val _error = MutableSharedFlow<String>(
        extraBufferCapacity = 1,
        onBufferOverflow = DROP_OLDEST
    )

    val error = _error.asSharedFlow()

    private val _errorDialog = MutableSharedFlow<String>(
        extraBufferCapacity = 1,
        onBufferOverflow = DROP_OLDEST
    )

    val errorDialog = _errorDialog.asSharedFlow()

    private val _connectionError = MutableSharedFlow<String>(
        extraBufferCapacity = 1,
        onBufferOverflow = DROP_OLDEST
    )
    val connectionError = _connectionError.asSharedFlow()


   init {
        loadData()
    }

    fun onRetryClick() {
        loadData()
    }

    private fun loadData() {
        viewModelScope.launch {
        flow { emit(interactor.getData()) }
            .onStart { startLoading() }
            .onCompletion { finishLoading() }
            .onEach { data ->
                //тут куча всяких данных
                _data.value = data.data
            }
            .catch { cause: Throwable -> setError(cause) }
            .collect()
        }
    }

    private fun startLoading() {
        _loading.value = true
    }

    private fun finishLoading() {
        _loading.value = false
    }

    private fun setError(throwable: Throwable) {
        when (throwable) {
            is BusinessException -> _errorDialog.tryEmit(throwable.message)
            is HttpException ->_connectionError.tryEmit(throwable.message)
            else ->_error.tryEmit(throwable.message)
        }
    }
}

//MainViewmodelUnitTest
class MainViewModelTest{

    /*
    init block
    Для моков используем например мокито
    */

    @Test
    fun `load data has BusinessException EXPECT errorDialog`(): Unit = runBlockingTest {

        interactor.stub {
            onBlocking { getData() } doThrow BusinessException("Error")
        }

        val testResults = mutableListOf<String>()
        val job = launch {
            viewModel.errorDialog.toList(testResults)
        }
        viewModel.onRetryClick()// Проблема в том,что если убрать это, то testResults будет пустой

        assertEquals(
            "Error",
            testResults.first()
        )

        job.cancel()
    }
}