java 中的模拟方法返回类型

Question

Below is main code consist of one util class and service class using it

@PropertySource("classpath:atlas-application.properties")
public class ApacheAtlasUtils {

  @Value("${atlas.rest.address}")
  private String atlasURL;
  
  @Value("${atlas.rest.user}")
  private String atlasUsername;

  @Value("${atlas.rest.password}")
  private String atlasPassword;

  private AtlasClientV2 client;

  public AtlasClientV2 createClient() {
    if (client == null) {
      return new AtlasClientV2(new String[] {atlasURL}, new String[] {atlasUsername, atlasPassword});
    } else {
      return client;
    }
  }
}

Service Class is below:-

@Override
  public Page<SearchResultDto> findFilesWithPages(QueryParent queryParent, Pageable pageable)
    throws AtlasServiceException {
    //  Some code
    client = new ApacheAtlasUtils().createClient();
   //some code
      
      }

  

I am writing unit test for service method and I am getting exception for createClient method asking for values for url, username and password which should not happen as this should be mocked but the mocking is giving me below error

java.lang.IllegalArgumentException: Base URL cannot be null or empty.

    at com.google.common.base.Preconditions.checkArgument(Preconditions.java:141)
    at org.apache.atlas.AtlasServerEnsemble.<init>(AtlasServerEnsemble.java:35)
    at org.apache.atlas.AtlasBaseClient.determineActiveServiceURL(AtlasBaseClient.java:318)
    at org.apache.atlas.AtlasBaseClient.initializeState(AtlasBaseClient.java:460)
    at org.apache.atlas.AtlasBaseClient.initializeState(AtlasBaseClient.java:448)
    at org.apache.atlas.AtlasBaseClient.<init>(AtlasBaseClient.java:132)
    at org.apache.atlas.AtlasClientV2.<init>(AtlasClientV2.java:82)
    at com.jlr.stratus.commons.utils.ApacheAtlasUtils.createClient(ApacheAtlasUtils.java:40)
    at com.jlr.stratus.rest.service.impl.FileSearchService.findFilesWithPages(FileSearchService.java:49)

The Test code is as follows:-

 private FileSearchService fileSearchService;

  @Spy
  private ApacheAtlasUtils apacheAtlasUtils;

  @Mock
  private AtlasClientV2 client;

  @Before
  public void setup() {
    MockitoAnnotations.initMocks(this);
    fileSearchService = new FileSearchService();
  }
  
@Test
  public void findFilesWithPages_searchAll() throws AtlasServiceException {
        Mockito.doReturn(client).when(apacheAtlasUtils).createClient();

   service.search(queryParent,pageable);

  } 
      

  
  
  

Answer 1

Your idea with spying is adequate (you can even go for mocking if you do not actually need any true implementation of that class).

The problem lies in the implementation:

    //  Some code
    client = new ApacheAtlasUtils().createClient();
   //some code
      
      }

Instead of having the ApacheAtlasUtils as an instance variable (or a supplier method) you create the instance on the fly.

Mockito is not smart enough to catch that operation and replace the real object with you spy.

With the supplier method you can set up your test as follows:

  @Spy
  private FileSearchService fileSearchService = new FileSearchService();

  @Spy
  private ApacheAtlasUtils apacheAtlasUtils = new ApacheAtlasUtils();

  @Mock
  private AtlasClientV2 client;

  @Before
  public void setup() {
    MockitoAnnotations.initMocks(this);

    doReturn(apacheAtlasUtils).when(fileSearchService).getApacheUtils();
  }

in your SUT:

@Override
  public Page<SearchResultDto> findFilesWithPages(QueryParent queryParent, Pageable pageable)
    throws AtlasServiceException {
    //  Some code
    client = getApacheUtils().createClient();
   //some code
      
      }

ApacheAtlasUtils getApacheUtils(){
   return new ApacheAtlasUtils();
}