android - 带有 mockito 测试的简单 kotlin 类导致 MissingMethodInvocationException

Question

我开始学习 Kotlin 和 Mockito，所以我编写了一个简单的模块来测试它。

AccountData_K.kt:

open class AccountData_K {
var isLogin: Boolean = false
var userName: String? = null

    fun changeLogin() : Boolean {
        return !isLogin
    }
}

AccountDataMockTest_K.kt:

class AccountDataMockTest_K {
    @Mock
    val accountData = AccountData_K()

    @Before
    fun setupAccountData() {
        MockitoAnnotations.initMocks(this)
    }

    @Test
    fun testNotNull() {
        assertNotNull(accountData)
    }

    @Test
    fun testIsLogin() {
        val result = accountData.changeLogin()
        assertEquals(result, true)
    }

    @Test
    fun testChangeLogin() {        
        `when`(accountData.changeLogin()).thenReturn(false)
        val result = accountData.changeLogin()
        assertEquals(result, false)
    }
}

当我运行测试时，它报告有关 testChangeLogin() 方法的异常:

org.mockito.exceptions.misusing.MissingMethodInvocationException: 
when() requires an argument which has to be 'a method call on a mock'.
For example:
    when(mock.getArticles()).thenReturn(articles);

Also, this error might show up because:
1. you stub either of: final/private/equals()/hashCode() methods.
   Those methods *cannot* be stubbed/verified.
2. inside when() you don't call method on mock but on some other object.
3. the parent of the mocked class is not public.
   It is a limitation of the mock engine.

at com.seal.materialdesignwithkotlin.AccountDataMockTest_K.testChangeLogin(AccountDataMockTest_K.kt:57)
...

我怀疑为什么这个方法不是对模拟的方法调用...

所以请帮助我，谢谢。

Answer 1

默认 Kotlin 的 classes and members are final . Mockito 无法 mock final classes nor methods .要使用 Mockito，您需要打开您希望模拟的方法:

open fun changeLogin() : Boolean {
    return !isLogin
}

进一步阅读

• Is it possible to use Mockito in Kotlin?
• Is it possible to use Mockito with Kotlin without open the class?

附言。以我的拙见，只要通过即 ISP 保持接口(interface)较小即可。 ，使用 Mockito 或其他模拟框架的测试代码很少比手写的假货/ stub 更易读和更容易理解。