felipelahti / feign-mock

An easy way to test https://github.com/Netflix/feign. Since using feign most of the logic is store into annotations this helps to check if the annotations are right.

feign-mock

An easy way to test https://github.com/Netflix/feign. Since using feign most of the logic is store into annotations this helps to check if the annotations are right.

Original article available here

If mocking feign clients is easy, testing the logic written in annotations is everything but!

To check if you are parsing the request/response properly the only way it firing a real request. Well, that doesn’t seem to be a good path to unit (or even integration) test remote services. Any IO change will affect test stability.

That is why I create feign-mock.

With feign-mock you can using pre-loaded json strings or streams as content for your responses. It also allow you to verify mock invokation and feign-mock will hit your annotations to make sure everything works.

Example

  private GitHub github;
  private MockClient mockClient;

  @Before
  public void setup() throws IOException {
    mockClient = new MockClient()
        .noContent(HttpMethod.PATCH, "/repos/velo/feign-mock/contributors");

    github = Feign.builder()
        .decoder(new GsonDecoder())
        .client(mockClient)
        .target(new MockTarget<>(GitHub.class));
  }

  @Test
  public void missHttpMethod() {
    List<Contributor> result = github.patchContributors("velo", "feign-mock");
    assertThat(result, nullValue());
    mockClient.verifyOne(HttpMethod.PATCH, "/repos/velo/feign-mock/contributors");
  }

This simple test returns no content and verify if the url was trully invoked.

On mock client, you can include all urls and methods you wanna mock.

For a more compreensive example take a look at MockClientTest.