PowerMockito无法模拟私有方法

Question

@Service
public class Topic_Service
{
   private String test_help()
   {
      return "test_help";
   }

   public String testing()
   {
      return test_help() + " " + "testing";
   }
}



//Test Code

@SpringBootTest
@RunWith(PowerMockRunner.class)
@PrepareForTest(Topic_Service.class)
class Topic_Service_test
{

   @InjectMocks
   private Topic_Service topic_service =  PowerMockito.spy(new 
   Topic_Service());

   @Test
   void testing_test() throws Exception
   {

     PowerMockito.when(topic_service,"test_help").thenReturn("hello");
     String s = topic_service.testing();
     Assertions.assertEquals("hello testing",s);
   }
}



//POM.XML Dependencies

    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>

    <dependency>
        <groupId>org.mockito</groupId>
        <artifactId>mockito-core</artifactId>
        <version> 2.8.47</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>org.powermock</groupId>
        <artifactId>powermock-module-junit4</artifactId>
        <version>1.7.0</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>org.powermock</groupId>
        <artifactId>powermock-api-mockito2</artifactId>
        <version>1.7.0</version>
        <scope>test</scope>
    </dependency>

有人能帮帮我吗？提前谢了。

Answer 1

您没有正确地插入私有方法。您需要使用PowerMockito.stub为私有方法存根。

下面是如何正确地建立私有方法的存根：

PowerMockito.stub(PowerMockito.method(Topic_Service.class,"test_help")).toReturn("hello");

我将您的代码修改如下：

@RunWith(PowerMockRunner.class)
@PrepareForTest(Topic_Service.class)
public class Topic_ServiceTest {

    @Test
    void testing_test() throws Exception {
        // Setup
        Topic_Service topic_serviceSpy = PowerMockito.spy(new Topic_Service());
        PowerMockito.doReturn("Hello").when(topic_serviceSpy, "test_help");
        // exercise
        String s = topic_serviceSpy.testing();
        // verify
        Assertions.assertEquals("hello testing",s);
    }

}