Testes para o PostsViewModel

PostsViewModelTest.kt

@Test
fun `should take posts and display it when call takePosts`() {
    // given
    val posts = listOf<Post>(mockk(), mockk())

    val observerDisplayingView = spyk<Observer<Int>>()
    val displayingViewResults = mutableListOf<Int>()

    val observerPostResult = spyk<Observer<List<Post>>>()
    val postResults = mutableListOf<List<Post>>()

    every { useCase.takePosts() } returns Single.just(posts)

    viewModel.displayingView.observeForever(observerDisplayingView)
    viewModel.postResult.observeForever(observerPostResult)

    // when
    viewModel.takePosts()

    // then
    verify { observerDisplayingView.onChanged(capture(displayingViewResults)) }
    verify { observerPostResult.onChanged(capture(postResults)) }

    assertThat(displayingViewResults).isEqualTo(
        listOf(
            PostsViewModel.DisplayingView.Loading.ordinal,
            PostsViewModel.DisplayingView.Success.ordinal
        )
    )

    assertThat(postResults.size).isEqualTo(1)
    assertThat(postResults.first()).isEqualTo(posts)
}