在Controller Mockito Junit测试用例中模拟一个接口的两种不同实现

Question

Interface  - Client
Impl class - PCleint, SClient

@Mock
private Client pclient

@Mock 
private Client sclient

如何区分模拟不同的impl类，从而调用impl类的方法。我应该像下面这样做吗。

@Mock
private PClient pclient

@Mock 
private SClient sclient

对我没有用。任何一个都抛出空指针异常。请指教。

Answer 1

我想技巧是您需要使用before来存根返回值，并为控制器使用@injectmocks。由于@mock不会返回“真实”对象，它只返回一个“mock”（或fake：p）对象。因此，当您调用这个“mock”对象的方法时，它不会返回方法的实际输出，而是返回null。这就是为什么您需要使用@before来存根返回。

请参阅下面的示例代码：

客户端接口

public interface Client {
    String someMethod();
}

public class PClient implements Client {
    private static final String name = "PClient";
    @Override
    public String someMethod() {
        return name;
    }
}


public class SClient implements Client{
    private static final String name = "SClient";
    @Override
    public String someMethod() {
        return name;
    }
}

客户端控制器

@Controller公共类ClientController{

@Autowired
private PClient pClient;
@Autowired
private SClient sClient;

public ClientController(){
}
public String executePClient(){
    return this.pClient.someMethod();
}

public String executeSClient(){
    return this.sClient.someMethod();
}

public String execute(Client client){
    return client.someMethod();
}

}

测试用例需要添加@before来存根方法返回。

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.junit.MockitoJUnitRunner;

import static org.junit.Assert.assertEquals;
import static org.mockito.Mockito.when;

@RunWith(MockitoJUnitRunner.class)
public class ClientControllerTest {
    @Mock
    private PClient pclient;
    @Mock
    private SClient sclient;
    @InjectMocks
    private ClientController clientController;

    @Before
    public void setup(){
        when(pclient.someMethod()).thenReturn(new PClient().someMethod());
        when(sclient.someMethod()).thenReturn(new SClient().someMethod());
    }

    @Test
    public void testPClient(){
        String result = clientController.executePClient();
        assertEquals("PClient",result);
    }

    @Test
    public void testSClient(){
        String result = clientController.executeSClient();
        assertEquals("SClient",result);
    }

    @Test
    public void testExecuteWithPClient(){
        String result = clientController.execute(pclient);
        assertEquals("PClient",result);
    }

    @Test
    public void testExecuteWithSClient(){
        String result = clientController.execute(sclient);
        assertEquals("SClient",result);
    }
}