@Test
 public void doesNotDefaultExceptionMappers() throws Exception {
   http.setRegisterDefaultExceptionMappers(false);
   assertThat(http.getRegisterDefaultExceptionMappers()).isFalse();
   Environment environment =
       new Environment(
           "test",
           Jackson.newObjectMapper(),
           Validation.buildDefaultValidatorFactory().getValidator(),
           new MetricRegistry(),
           ClassLoader.getSystemClassLoader());
   http.build(environment);
   for (Object singleton : environment.jersey().getResourceConfig().getSingletons()) {
     assertThat(singleton).isNotInstanceOf(ExceptionMapper.class);
   }
 }