@Test
public void getUpcomingBirthdays() throws Exception {

    server.enqueue(new MockResponse().setBody("{\n"
          + "  \"users\": [\n"
          + file("user.json") + ','
          + file("user.json") + ','
          + file("user.json")
          + "  ]\n"
          + '}'));
    Response<List<XingUser>, HttpError> response = resource.getUpcomingBirthdays().execute();
    // If no exception was thrown then the spec is build correctly.
    assertThat(response.body().size()).isEqualTo(3);
}