使用Robolectric和PowerMock生成零%代码覆盖率的领域单元测试

Question

我遵循了这里的说明：

null

@RunWith(RobolectricTestRunner.class)
@PowerMockIgnore({"org.mockito.*", "org.robolectric.*", "android.*"})
@PrepareForTest({Realm.class, RealmConfiguration.class, RealmCore.class, RealmLog.class})
@SuppressStaticInitializationFor("io.realm.internal.Util")
@Config(constants = BuildConfig.class, manifest =    "src/main/AndroidManifest.xml", sdk = 21)
public class DecisionTreeTest
{
    @Captor
    ArgumentCaptor<Realm.Transaction.Callback> realmCallbackCaptor;

    // Robolectric, Using Power Mock https://github.com/robolectric/robolectric/wiki/Using-PowerMock
    @Rule
    public PowerMockRule rule = new PowerMockRule();

    private Context mockContext;

    private final byte[] fakeRealmKey = {
        -122, -115, -113, -111, -105, -104, -101, -99, -94, -93, -90, -87,
        -77, -74, -67, -66, -63, -61, -56, -53, -48, -47, -33, -31,
        -30, -28, -22, -17, -5, -3, -1, 3, 8, 11, 17, 18,
        21, 22, 27, 30, 40, 42, 51, 52, 53, 54, 57, 59,
        61, 63, 67, 70, 74, 76, 78, 85, 90, 91, 103, 108,
        113, 117, 119, 127
    };

    @Before
    public void setUp() throws Exception
    {
        // Setup Realm to be mocked. The order of these matters
        mockStatic(RealmCore.class);
        mockStatic(RealmLog.class);
        mockStatic(Realm.class);
        mockStatic(RealmConfiguration.class);

        this.mockContext = RuntimeEnvironment.application;

        Whitebox.setInternalState(
                Realm.class,
                "applicationContext",
                RuntimeEnvironment.application);

        /*
        Better solution would be just mock the RealmConfiguration.Builder class.
        But it seems there is some problems for powermock to mock it (static inner class).
        We just mock the RealmCore.loadLibrary(Context) which will be called by
        RealmConfiguration.Builder's constructor.
        */
        doNothing().when(RealmCore.class);
        RealmCore.loadLibrary(any(Context.class));
    }

    @Test(expected = DecisionTreeException.class)
    public void persistSurvey_DecisionTreeRealmNotEnabled_ThrowsException() throws Exception
    {
        DecisionTree decisionTree = createSimpleDecisionTree();
        Survey survey = decisionTree.getSurveyFromResource(R.raw.survey);
        decisionTree.persistSurvey(survey, null, null);
    }

    @Test(expected = DecisionTreeException.class)
    public void persistSurvey_NullAsFirstParam_ThrowsException() throws Exception
    {
        DecisionTree decisionTree = createRealmDecisionTree();
        decisionTree.persistSurvey(null, null, null);
    }

    @Test
    public void persistSurvey_SurveyAsFirstParam_ThrowsException() throws Exception
    {
        final Realm mockRealm = mock(Realm.class);
         when(Realm.getInstance(any(RealmConfiguration.class))).thenReturn(mockRealm);

        org.mockito.stubbing.Answer<Void> executeAnswer = new org.mockito.stubbing.Answer<Void>()
        {
            @Override
            public Void answer(InvocationOnMock invocation) throws Throwable
            {
                ((Realm.Transaction) invocation.getArguments()[0]).execute(mockRealm);
                return null;
            }
        };

        doAnswer(executeAnswer)
            .when(mockRealm)
            .executeTransactionAsync(
                    any(Realm.Transaction.class),
                    any(Realm.Transaction.OnSuccess.class),
                    any(Realm.Transaction.OnError.class));

        DecisionTree decisionTree = createRealmDecisionTree();
        Survey survey = decisionTree.getSurveyFromResource(R.raw.survey);

        decisionTree.persistSurvey(survey, null, null);

        verify(mockRealm).executeTransactionAsync(
            any(Realm.Transaction.class),
            any(Realm.Transaction.OnSuccess.class),
            any(Realm.Transaction.OnError.class));
        verify(mockRealm).copyToRealmOrUpdate(any(Survey.class));
    }

    private DecisionTree createRealmDecisionTree()
    {
        return new DecisionTree.Builder()
            .setContext(mockContext)
            .setRealmKey(fakeRealmKey)
            .setRealmEnabled(true)
            .build();
    }

    private DecisionTree createSimpleDecisionTree()
    {
        return new DecisionTree.Builder()
            .setContext(RuntimeEnvironment.application)
            .build();
    }
}

我认为，问题出在下面这一行：

@Rule
public PowerMockRule rule = new PowerMockRule();

但是，如果删除这一行，尽管@PrepareForTest行不变，但会出现以下错误：

org.powermock.api.mockito.ClassNotPreparedException: 
The class io.realm.internal.RealmCore not prepared for test.
To prepare this class, add class to the '@PrepareForTest' annotation.
In case if you don't use this annotation, add the annotation on class or  method level.

Answer 1

我猜你是在利用Jacoco来收集报道。PowerMock与Jacoco/Eclemma之间存在一个已知的问题。我们将在下一个版本中修复它。

更新：PowerMock 1.6.6已经发布。它包括JaCoCo脱机检测代码的修复。因此，现在您可以通过使用JaCoCo maven插件和离线检测获得代码覆盖率