NewsListingFragmentTest.kt

internal fun stubNews(single: Single<List<NewsModel>> = Single.just(mock())) {
    whenever(TestApplication.getMockedDataManager().getNews(any())).thenReturn(single)
  }

test_app_module.kt

val testAppModule = applicationContext {

  bean<ThreadExecutor> {
    JobExecutor()
  }

  bean<PostExecutionThread> {
    UiThread()
  }

  bean<NetworkManager> {
    mock()
  }

  bean<PersistenceManager> {
    mock()
  }

  bean<DataManager> {
    mock()
  }

  bean<ErrorMessageFactory> {
    ErrorMessageFactoryImpl(get())
  }

  bean<DeviceIdManager> {
    DeviceIdAndroidManager(get())
  }

}

TestApplication.kt

class TestApplication : Application() {

  override fun onCreate() {
    super.onCreate()
    startKoin(this, listOf(testAppModule)
  }

  companion object {
    fun getMockedDataManager() : DataManager {
      return (StandAloneContext.koinContext as KoinContext).get { emptyMap() }
    }
  }
}