Question

在测试我的应用程序时需要一些帮助。我想验证视图模型是否有趣 writeNewTask（）。它必须将 Task 对象添加到数据库中，该对象位于每个任务的父级 tasks 和个人 id 下。

fun writeNewTask(name: String?, orphanage: String?) {
        val id = database.push().key!!
        val task = Task(id, name, orphanage)
        database.child("tasks").child(id).setValue(task)
    }

我正在使用PowerMock。因此，这就是我的测试样子

@RunWith(PowerMockRunner::class)
@PowerMockRunnerDelegate(JUnit4::class)
@PrepareForTest(FirebaseDatabase::class, AddTaskViewModel::class, DatabaseReference::class)
@PowerMockIgnore("org.mockito.*", "org.robolectric.*", "android.*", "androidx.*")
class AddTaskViewModelTest {

    @Mock
    lateinit var mockedDatabase: FirebaseDatabase
    @Mock
    lateinit var databaseReference: DatabaseReference
    @Mock
    lateinit var viewModel: AddTaskViewModel

    @Before
    fun before() {
        viewModel = PowerMockito.mock(AddTaskViewModel::class.java)
        databaseReference = PowerMockito.mock(DatabaseReference::class.java)

        PowerMockito.mockStatic(AddTaskViewModel::class.java)
        PowerMockito.mockStatic(DatabaseReference::class.java)

        PowerMockito.mockStatic(FirebaseDatabase::class.java)
        `when`(FirebaseDatabase.getInstance()).thenReturn(mockedDatabase)

        mockedDatabase = PowerMockito.mock(FirebaseDatabase::class.java)
        `when`(mockedDatabase.reference).thenReturn(databaseReference)
    }

    @Test
    fun writeNewTaskTest() {
        val id = "1"
        `when`(databaseReference.key).thenReturn(id)
        val name = "name"
        val orphanage = "orphanage"
        val task = Task(id, name, orphanage)

        viewModel.writeNewTask(name, orphanage)

        verify(databaseReference)
            .child("tasks")
            .child(id)
            .setValue(task)
    }
}

我发现了这个错误。调试后，我发现 child（“ tasks”）为 null

databaseReference.child("tasks");
-> at com.example.application.viewModel.AddTaskViewModelTest.writeNewTaskTest(AddTaskViewModelTest.kt:59)
Actually, there were zero interactions with this mock.

Wanted but not invoked:
databaseReference.child("tasks");
-> at com.example.application.viewModel.AddTaskViewModelTest.writeNewTaskTest(AddTaskViewModelTest.kt:59)
Actually, there were zero interactions with this mock.

Answer 1

之所以会发生这种情况，是因为您对数据库的引用与ViewModel中的引用不同。因此，让我们假设您有一个ViewModel可以在构造器中获取这样的数据库：

class AddTaskViewModel(private val database: FirebaseDatabase): ViewModel()

因此，要测试ViewModel，您需要创建其实例，而不是对其进行模拟。您的代码中的内容应如下所示：

@Before
fun before() {
    databaseReference = mock(DatabaseReference::class.java)
    mockedDatabase = mock(FirebaseDatabase::class.java)
    `when`(mockedDatabase.reference).thenReturn(databaseReference)

    viewModel = AddTaskViewModel(mockedDatabase)
}

此外，您不需要PowerMockito进行测试，Mockito本身就足够了

Android Firebase Junit4模拟数据库。如何模拟数据库子级？

1 个答案: