我无法使用Mockito和PowerMockito模拟静态方法

Question

I'm having trouble mocking a static method in a third-party library. I keep receiving a null-pointer exception when running the test, but I'm not sure why that is.

Here is the class and the void method that invokes the static method I'm trying to mock " MRClientFactory.createConsumer(props) ":

public class Dmaap {

    Properties props = new Properties();
    public Dmaap() {

    }

    public MRConsumerResponse createDmaapConsumer() {
        System.out.println("at least made it here");
        MRConsumerResponse mrConsumerResponse = null;
        try {
            MRConsumer mrConsumer = MRClientFactory.createConsumer(props);
            System.out.println("made it here.");
            mrConsumerResponse = mrConsumer.fetchWithReturnConsumerResponse();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace(); 
        }

        return mrConsumerResponse;      
    }
}

Below is the test that keeps returning a null-pointer exception. The specific line where the null-pointer is being generated is: MRClientFactory.createConsumer(Mockito.any(Properties.class));

@RunWith(PowerMockRunner.class)
@PrepareForTest(fullyQualifiedNames = "com.vismark.PowerMock.*")
public class DmaapTest {

    @Test
    public void testCreateDmaapConsumer() {
        try {
            Properties props = new Properties();
            PowerMockito.mockStatic(MRClientFactory.class);

            PowerMockito.doNothing().when(MRClientFactory.class);

            MRClientFactory.createConsumer(Mockito.any(Properties.class));

            //MRClientFactory.createConsumer(props);

            Dmaap serverMatchCtrl = new Dmaap();
            Dmaap serverMatchCtrlSpy = spy(serverMatchCtrl);

            serverMatchCtrlSpy.createDmaapConsumer();

        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

Answer 1

Please follow this example carefully: https://github.com/powermock/powermock/wiki/MockStatic

Especially you are missing a

@PrepareForTest(Dmaap.class)

…to denote the class which does the static call.