@Test
  public void testCall_unknown() throws IOException, RegistryException {
    ResponseException responseException =
        mockResponseException(HttpStatusCodes.STATUS_CODE_SERVER_ERROR);
    setUpRegistryResponse(responseException);

    try {
      endpointCaller.call();
      Assert.fail("Call should have failed");

    } catch (ResponseException ex) {
      Assert.assertSame(responseException, ex);
    }
  }
Implementation of {@link RegistryEndpointProvider} for testing.
jib-core/src/test/java/com/google/cloud/tools/jib/registry/RegistryEndpointCallerTest.java