如何在Spring测试中给一个bean注入价值？

Question

我这里有一个问题，请给出一些想法。

我有两个豆子。FaceComparisonServerImpl依赖于FaceServer。当我想测试的时候。我想更改我的'FaceServer'bean中的字符串。

@Service        
public class FaceComparisonServerImpl implements FaceComparisonServer {
            
    @Autowired
    private FaceServer faceServer;

    @Override
    public FaceComparsionInfo getServerInfo() {
        String serverInfo = faceServer.getServerInfo();
        ...

    }
         
}

@Component
public class FaceServer {

    @Autowired
    private RestTemplate restTemplate;

    //Not final, just to test.
    private String version = "1.0";
    private static final String CODE = "code";
    private static final String MESSAGE = "message";
    //Final
    private static final String SERVER_URL = "http://127.0.0.1:8066/api/ZKComparison";
}

贝娄是我的测试代码。

@ExtendWith(SpringExtension.class)
@ContextConfiguration(classes = TestConfig.class)
public class FaceServerTestByTyler {

    @Autowired
    private FaceComparisonServer faceComparisonServer;

    @Test
    public void getServerInfo(){
        //How can i modify the value of SERVER_URL in faceServer？
        FaceComparsionInfo serverInfo = faceComparisonServer.getServerInfo();
        System.out.println(serverInfo);
    }
}

我的问题是：我如何修改@bean(faceServer)中'version'和'server_url'的值？

谢谢你！

Answer 1

自定义值的最简单方法是使其成为Spring属性：

@Component
public class FaceServer {

    @Value("${faceServer.version}")
    private String version;
    @Value("${faceServer.url}")
    private String serverUrl;

    // ...
}

您可以为@value批注设置默认值，也可以在application.yml中使用一些默认属性值。

现在只需在测试中用所需的值重写这些属性：

@ExtendWith(SpringExtension.class)
@ContextConfiguration(classes = TestConfig.class)
@TestPropertySource(properties = {
    "faceServer.version=1.0",
    "faceServer.url=http://127.0.0.1:8066/api/ZKComparison"
})
public class FaceServerTestByTyler {

    @Autowired
    private FaceComparisonServer faceComparisonServer;

    // ...
}

然而...

第二种选择是使类具有更好的单元可测试性。更喜欢构造注入而不是字段注入，并且您可以更独立地测试您的类。

@Service        
public class FaceComparisonServerImpl implements FaceComparisonServer {
            
    private final FaceServer faceServer;

    public FaceComparisonServerImpl(FaceServer faceServer) {
        this.faceServer = faceServer;
    }

    @Override
    public FaceComparsionInfo getServerInfo() {
        String serverInfo = faceServer.getServerInfo();
        // ...

    }     
}

这现在变成了单元可测试的：

public class FaceServerTestByTyler {

    private FaceComparisonServer faceComparisonServer;
    private FaceServer faceServer;

    @BeforeEach
    public setup() {
        faceServer = mock(FaceServer.class);
        faceComparisonServer = new FaceComparisonServer(faceServer);
    }

    @Test
    public void getServerInfo() {
        when(faceServer.getServerInfo()).thenReturn(xxx);
        // ...
    }
}

第二个选项最终得到一个测试，它的运行速度比任何建议通过测试配置创建模拟bean的解决方案都快得多。