无法测试使用Coroutines的代码，并使用Mockito暂停功能

Question

我正在尝试使用MVP编写一个应用程序，并适应我用来在Java中编写的异步存储库模式使用Kotlin的悬浮函数。但是，我还没有能够正确测试使用暂停功能的代码。我越多地进行了测试，并且与我认为模拟不返回应该返回的对象而失败，而是零。

这是一个显示问题的小应用程序：

UserRepository(getUser()方法在返回虚拟用户和抛出异常之间交替(：

interface UserRepository {
    suspend fun getUser(): User
}
class UserRepositoryImpl : UserRepository {
    var shouldWork = false
    override suspend fun getUser(): User {
        shouldWork = !shouldWork
        if (shouldWork) {
            return User("Mr. User", "[e-mail]")
        } else {
            throw UnableToFetchUserInfoException()
        }
    }
}

视图：

interface MainView {
    fun showUserInfo(user: User)
    fun hideUserInfo()
    fun showFailedToLoadUserInfoIndicator()
    fun hideFailedToLoadUserIndicator()
}
class MainActivity : AppCompatActivity(), MainView {
    private lateinit var presenter: MainPresenter
    override fun showUserInfo(user: User) {
        userInfo.text = user.toString()
    }
    override fun hideUserInfo() {
        userInfo.text = ""
    }
    override fun showFailedToLoadUserInfoIndicator() {
        Toast.makeText(this, "Failed to get user info", Toast.LENGTH_SHORT).show()
    }
    override fun hideFailedToLoadUserIndicator() {
        // nothing to do. It's a toast.
    }
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        presenter = MainPresenterImpl(this, UserRepositoryImpl(), UI)
        button.setOnClickListener {
            presenter.onFetchUserButtonClicked()
        }
    }

}

主持人：

interface MainPresenter {
    fun onFetchUserButtonClicked()
}
class MainPresenterImpl(private val view: MainView,
                        private val userRepository: UserRepository,
                        private val coroutineContext: CoroutineContext) : MainPresenter {
    override fun onFetchUserButtonClicked() {
        launch(coroutineContext) {
            view.hideFailedToLoadUserIndicator()
            try {
                val user = userRepository.getUser()
                view.showUserInfo(user)
            } catch (ex: UnableToFetchUserInfoException) {
                view.hideUserInfo()
                view.showFailedToLoadUserInfoIndicator()
            }
        }
    }
}

和测试：

@Test
fun `should show user info on the view when the user request finishes succesfully`() = runBlocking {
    presenter = MainPresenterImpl(viewMock, userRepositoryMock, CommonPool)
    val expectedUser = User("Test", "[e-mail]")
    whenever(runBlocking { userRepositoryMock.getUser() } ).thenReturn(expectedUser)
    presenter.onFetchUserButtonClicked()
    verify(viewMock, times(1)).showUserInfo(expectedUser)
}

输出...

Argument(s) are different! Wanted:
mainView.showUserInfo(
    User(name=Test, email=[e-mail])
);
-> at com.pablobr9.suspendwithtests.MainPresenterImplTest$should show user info on the view when the user request finishes succesfully$1.doResume(MainPresenterImplTest.kt:40)
Actual invocation has different arguments:
mainView.showUserInfo(
    null
);
-> at com.pablobr9.suspendwithtests.MainPresenterImpl$onFetchUserButtonClicked$1.doResume(MainPresenterImpl.kt:15)

我尝试了很多事情，但是我仍然无法使用Kotlin中使用悬挂功能/Coroutines编写可测试的MVP应用程序。甚至不能像这样简单做到这一点。我在这里缺少什么？

Answer 1

修复程序已经在Mockito Lib中，https://github.com/nhaarman/mockito-kotlin/pull/171

验证您是否将mockito-core 显式也进入依赖项列表，例如：

dependencies {
    // other dependencies...
    // mockito...
    testImplementation "org.mockito:mockito-core:2.13.0"
    // mockito kotlin...
    testImplementation "com.nhaarman:mockito-kotlin:1.5.0"
}