Kotlin中含await()的协程如何测试？mockk测试无响应排查

我尝试用MockK为包含await()的挂起函数编写测试，但测试始终无法结束。请问当前测试方法是否正确？有没有遗漏步骤？

测试代码 #

private lateinit var repository: AuthRepository
private lateinit var databaseReference: DatabaseReference
private lateinit var auth: FirebaseAuth

@Before
fun setUp() {
    mockkStatic(FirebaseAuth::class)
    auth = mockk()
    databaseReference = mockk()
    every { FirebaseAuth.getInstance() } returns auth
    repository = AuthRepository(databaseReference)
}

@Test
fun login_Successful() = runBlocking {
    val email = "test@example.com"
    val password = "password"
    val authResult: AuthResult = mockk()
    val expectedResult = Resource.Success(authResult)

    coEvery { auth.signInWithEmailAndPassword(email, password).await() } returns authResult

    val result = repository.login(email, password)

    Assert.assertEquals(expectedResult, result)
}

待测试代码 #

private val auth = FirebaseAuth.getInstance()

suspend fun login(email: String, password: String): Resource<AuthResult> =
    try {
        val authResult = auth.signInWithEmailAndPassword(email, password).await()
        Resource.Success(authResult)
    } catch(e: FirebaseAuthException) {
        Resource.Error(e.errorCode)
    }

问题原因 #

测试无法结束的核心问题是：你直接在coEvery中mock了await()调用，但signInWithEmailAndPassword返回的AuthResultTask是未被mock的真实对象，它的await()方法会阻塞当前协程——真实的Task没有实际执行环境，会一直处于pending状态，导致测试卡住。

修复方案 #

需要分两步mock：先让signInWithEmailAndPassword返回一个mock的Task对象，再对这个mock对象的await()方法指定返回值。

修改后的测试代码：

private lateinit var repository: AuthRepository
private lateinit var databaseReference: DatabaseReference
private lateinit var auth: FirebaseAuth

@Before
fun setUp() {
    mockkStatic(FirebaseAuth::class)
    auth = mockk()
    databaseReference = mockk()
    every { FirebaseAuth.getInstance() } returns auth
    repository = AuthRepository(databaseReference)
}

@Test
fun login_Successful() = runBlocking {
    val email = "test@example.com"
    val password = "password"
    val authResult: AuthResult = mockk()
    // 新增：mock Task对象
    val authTask: Task<AuthResult> = mockk()
    val expectedResult = Resource.Success(authResult)

    // 第一步：mock signInWithEmailAndPassword返回mock的Task
    every { auth.signInWithEmailAndPassword(email, password) } returns authTask
    // 第二步：mock Task的await()方法返回预期结果
    coEvery { authTask.await() } returns authResult

    val result = repository.login(email, password)

    Assert.assertEquals(expectedResult, result)
}

额外补充 #

• 测试Firebase的Task.await()时，必须确保Task本身是mock对象，否则真实Task会因无执行环境一直阻塞协程
• 若要测试异常分支（比如FirebaseAuthException），可在coEvery中指定抛出异常：

coEvery { authTask.await() } throws FirebaseAuthException("error_code", "error_message")

内容的提问来源于stack exchange，提问作者Kleini