java - 使用 PowerMockito 模拟私有(private)方法

Question

我正在使用 PowerMockito 来模拟私有(private)方法调用 (privateApi)，但它仍然会发出 privateApi 调用，进而发出另一个thirdPartCall。当 ThirdPartyCall 抛出异常时，我遇到了问题。据我了解，如果我模拟 privateApi，它不应该进入方法实现细节并返回模拟响应。

public class MyClient {

    public void publicApi() {
        System.out.println("In publicApi");
        int result = 0;
        try {
            result = privateApi("hello", 1);
        } catch (Exception e) {
            Assert.fail();
        }
        System.out.println("result : "+result);
        if (result == 20) {
            throw new RuntimeException("boom");
        }
    }

    private int privateApi(String whatever, int num) throws Exception {
        System.out.println("In privateAPI");
        thirdPartyCall();
        int resp = 10;
        return resp;
    }

    private void thirdPartyCall() throws Exception{
        System.out.println("In thirdPartyCall");
        //Actual WS call which may be down while running the test cases
    }
}

这是测试用例:

@RunWith(PowerMockRunner.class)
@PrepareForTest(MyClient.class)
public class MyclientTest {

    @Test(expected = RuntimeException.class)
    public void testPublicAPI() throws Exception {
        MyClient classUnderTest = PowerMockito.spy(new MyClient());
        PowerMockito.when(classUnderTest, "privateApi", anyString(), anyInt()).thenReturn(20);
        classUnderTest.publicApi();
    }
}

控制台跟踪:

In privateAPI
In thirdPartyCall
In publicApi
result : 20

Answer 1

您只需更改模拟方法调用即可使用doReturn。

Example Partial Mocking of Private Method

测试代码

@RunWith(PowerMockRunner.class)
@PrepareForTest(MyClient.class)
public class MyClientTest {

    @Test(expected = RuntimeException.class)
    public void testPublicAPI() throws Exception {
        MyClient classUnderTest = PowerMockito.spy(new MyClient());

        // Change to this  

        PowerMockito.doReturn(20).when(classUnderTest, "privateApi", anyString(), anyInt());

        classUnderTest.publicApi();
    }
}

控制台跟踪

In publicApi
result : 20