PowerMockito在spring boot中模拟私有方法

Question

我正在尝试在我的类中测试一个私有方法，如下所示。

public String processPayment(...) {
    //some lines
    privateMethod(...);
    return "";
}

private Object privateMethod(...) {
    //some lines
    return someObject;
}

现在我需要测试processPayment方法并模拟privateMethod。

我尝试创建上述类的间谍，但是当我在下面执行时调用该方法

final DeviceCheckoutServiceImpl spyDeviceCheckoutService = spy(injectedMockBeanOfAboveClass); //@InjectMock in test class
PowerMockito.doReturn(null).when(spyDeviceCheckoutService, "privateMethod", ArgumentMatchers.anyMap()); //method gets called here
spyDeviceCheckoutService.processPayment(...); //private method isn't mocked somehow, and gets called here too

privateMethod在第二线本身被召唤。此外，the privateMethod没有被嘲笑。

也许我以错误的方式创建间谍对象？不能做spy(new DeviceCheckoutServiceImpl());因为它需要bean实例化。

Powermockito版本：

compile group: 'org.powermock', name: 'powermock-module-junit4', version: '2.0.0'
compile group: 'org.powermock', name: 'powermock-api-mockito2', version: '2.0.0'

让我知道我在这里做错了什么。

Answer 1

在测试类中，我们将通过将引用传递给需要测试的类来调用org.powermock.api.mockito.PowerMockito的spy（）方法：

MockPrivateMethodExample spy = PowerMockito.spy(mockPrivateMethodExample);

然后我们定义在调用这个特定的私有方法时我们想要做什么。

PowerMockito.doReturn("Test").when(spy, {$methodName});

mock private method example.Java

public class MockPrivateMethodExample {

  public String getDetails() {
    return "Mock private method example: " + iAmPrivate();
  }

  private String iAmPrivate() {
    return new Date().toString();
  }
}

mock private method test.Java

@RunWith(PowerMockRunner.class)
@PrepareForTest(MockPrivateMethodExample.class)
public class MockPrivateMethodTest {

  private MockPrivateMethodExample mockPrivateMethodExample;

  // This is the name of the private method which we want to mock
  private static final String METHOD = "iAmPrivate";

  @Test
  public void testPrivateMethod() throws Exception {
    mockPrivateMethodExample = new MockPrivateMethodExample();

    MockPrivateMethodExample spy = PowerMockito.spy(mockPrivateMethodExample);
    PowerMockito.doReturn("Test").when(spy, METHOD);
    String value = spy.getDetails();

    Assert.assertEquals(value, "Mock private method example: Test");
    PowerMockito.verifyPrivate(spy, Mockito.times(1)).invoke(METHOD);
  }
}

更多细节在这里：https://examples.javacodegeeks.com/core-java/mockito/mockito-mock-private-method-example-with-powermock/

Answer 2

Mockito介绍了AdditionalAnswers.delegatesTo来支持对Spring代理和其他类似事件的间谍：

看看这个问题：https://github.com/mockito/mockito/issues/529#issuecomment-239494581

因此，而不是spy(proxy)使用

mock(TestSubject.class,
  delegatesTo(springProxy))

。

但是，如果需要阅读注释，那么您将需要mockito 2 beta。因为mockito 1.x使用的CGLIB不会复制mockito子类上的注释。 Mockito 2使用了很棒的bytebuddy。

Answer 3

问题解决了！忘记在测试课上添加@PrepareForTest(DeviceCheckoutServiceImpl.class)了。