RegistryEndpointProvider<Optional<URL>> initializer() {
    return new Initializer();
  }
@Test
  public void testInitializer_handleResponse_unrecognized() throws IOException, RegistryException {
    Mockito.when(mockResponse.getStatusCode()).thenReturn(-1); // Unrecognized
    try {
      testBlobPusher.initializer().handleResponse(mockResponse);
      Assert.fail("Multiple 'Location' headers should be a registry error");

    } catch (RegistryErrorException ex) {
      MatcherAssert.assertThat(
          ex.getMessage(), CoreMatchers.containsString("Received unrecognized status code -1"));
    }
  }