ViewModelBuilder.kt

private inner class ViewModelBuilder {

    fun withLoadingData(): ViewModelBuilder {
        // For RxJava it would be every { someInteractor.loadSomething() } returns Single.never()
        coEvery { someInteractor.loadSomething() } coAnswers {
            delay(1_000)
            "result is not important"
        }
       return this
    }

    fun withDataLoadedWithError(throwable: Throwable): ViewModelBuilder {
        coEvery { someInteractor.loadSomething() } coAnswers { throw throwable }
        return this
    }

    fun withLoadedData(dataToLoad: String): ViewModelBuilder {
        coEvery { someInteractor.loadSomething() } returns dataToLoad
       return this
    }

    fun build(testScheduler: TestCoroutineScheduler): SomeViewModel {
        val dispatechers = TestDispatchersProvider(testScheduler)
        val viewModel = SomeViewModel(someInteractor, dispatechers)
        return viewModel
      }
}