mocking OkHttpClient 与 Mockito 时出错

Question

I want to write test for the below method in Junit5 with Mockito.

 public List<Data> getData(Long id) {
        UriComponents uriComponents = UriComponentsBuilder.fromUriString("test.com")
                .pathSegment("/test")
                .queryParam("filters[id]", id)
                .build();
    
        Request request = new Request.Builder()
                .url(uriComponents.toUriString())
                .method("GET", null)
                .build();
    
        try {
            Response response;
            response = okHttpClient.newCall(request).execute();
    
            TypeReference<List<Data>> listType = new TypeReference<>() {};
            List<Data> list = objectMapper.readValue(Objects.requireNonNull(response.body()).string(), listType);
            response.close();
    
            return list;
        } catch (IOException ioEx) {
            throw new RuntimeException(ioEx);
        }
    }

Test

 @Test
    public void shouldReturnData() throws IOException {
        try (MockedStatic<UriComponentsBuilder> mocked = mockStatic(UriComponentsBuilder.class)) {
            mocked.when(() -> UriComponentsBuilder.fromUriString("test.go").pathSegment("test")
                    .queryParam("filters[1]").build()).thenReturn(uriComponents);

            TypeReference<List<Data>> listType = new TypeReference<>() {};
            List<Data> expectedData = new ObjectMapper().readValue("{}", listType);
            List<Data> actualData = MyClient.getData(1234L);

            Assertions.assertEquals(expectedData, actualData);
        }
    }

The test is failing with below exception:-

org.mockito.exceptions.misusing.WrongTypeOfReturnValue: 
UriComponents$MockitoMock$2089413864 cannot be returned by fromUriString()
fromUriString() should return UriComponentsBuilder

I am unable to mock UriComponentsBuilder because of this exception.Can anyone please help here?

Answer 1

You are attempting to mock four method calls in this line:

    mocked.when(() -> UriComponentsBuilder.fromUriString("test.go").pathSegment("test")
            .queryParam("filters[1]").build()).thenReturn(uriComponents);

You can't do this. You can only mock one method call at a time.

If you want to mock out UriComponentsBuilder , then you will have to create a mock UriComponentsBuilder , mock the pathSegment and queryParam methods to return the mock UriComponentsBuilder instance, and finally mock the build() method to return uriComponents :

    UriComponentsBuilder uriComponentsBuilder = mock(UriComponentsBuilder.class);
    mocked.when(() -> UriComponentsBuilder.fromUriString("test.go"))
        .thenReturn(uriComponentsBuilder); 
    when(uriComponentsBuilder.pathSegment("test")).thenReturn(uriComponentsBuilder);
    when(uriComponentsBuilder.queryParam("filters[1]")).thenReturn(uriComponentsBuilder);
    when(uriComponentsBuilder.build()).thenReturn(uriComponents);