Mockito验证lambda被称为n次

如何解决Mockito验证lambda被称为n次

我需要测试一个lambda函数是否从服务实例中被调用了n次。

我有一个与存储库交互的Service类，当从存储库检索数据时发生错误时，该服务应重试，直到达到最大重试次数为止，因此我实现了以下操作：

interface Repository {
   Collection<String> getData();
}

public class RetryHelper<T> {

    private Integer retries;

    public RetryHelper(Integer retries) {
        this.retries = retries;
    }

    public interface Operation<T> {
        T doIt() throws Exception;
    }

    public T doWithRetry(Operation<T> operation) throws Exception {
        int remainRetries = retries;
        do {
            try {
                return operation.doIt();
            } catch (Exception e) {
                if (remainRetries == 0) {
                    throw e;
                }
                //TODO: wait before retry
                remainRetries--;
            }
        } while (true);
    }
}

class Service {
   @Inject
   Repository repo;

   private final RetryHelper<Collection<String>> retryHelper;

   public Collection<String> callService() {
        try {
            Collection<String> res = retryHelper.doWithRetry(() ->
                repo.getData());
            return res;
        } catch (Exception e) {
            throw (CustomException) e;
        }
   }

}

我需要使用Mockito测试发生错误时repo.getData()被称为n次。我可以更改Service代码和RetryHelper，因此可以提出建议。

我已尝试按照以下教程和文档进行测试：

public class ServiceTest {

    @Inject
    Service service;

    @InjectMock
    Repository repository;

    @InjectMock
    RetryHelper<Collection<String>> retryHelper;


    @Captor
    ArgumentCaptor<RetryHelper.Operation<Collection<String>>> operation;

    @BeforeEach
    void init_mocks() {
        MockitoAnnotations.openMocks(this);
    }

    @Test
    void shouldRetryIfDataQueryFailsForNonFatalError() throws Exception {
        when(repository.getData())
            .thenThrow(new RuntimeException("Runtime Exception"));

        service.callService();

        verify(retryHelper).doWithRetry(operation.capture());

        verify(repository,times(2)).getData();

    }
}

测试失败，并显示一条消息，即从未调用getData()。

解决方法

我终于找到了不使用Captor

的解决方案

public class ServiceTest {

    @Inject
    Service service;

    @InjectMock
    Repository repository;

    @Inject
    RetryHelper<Collection<String>> retryHelper;


    @Test
    void shouldRetryIfDataQueryFailsForNonFatalError() throws Exception {
        when(repository.getData())
            .thenThrow(new RuntimeException("Runtime Exception"));
        
        try {
           service.callService();
        } catch(Exception e) {
             verify(repository,times(2)).getData();
        }

    }
}