@Test
    public void shouldReturn501OnAuthFailureWithNoWwwAuthenticateHeaderSet() {
      when(response.getStatus()).thenReturn(401);

      final FilterDirector responseDirector = handler.handleResponse(request, response);

      assertEquals(
          "Auth component must identify proxy auth failures",
          HttpStatusCode.INTERNAL_SERVER_ERROR,
          responseDirector.getResponseStatus());
    }
    @Test
    public void shouldReturn501OnAuth501FailureWithDelegatedWwwAuthenticateHeaderNotSet() {
      when(response.getHeader(CommonHttpHeader.WWW_AUTHENTICATE.toString()))
          .thenReturn("Not-Delegate");
      when(response.getStatus()).thenReturn(501);

      final FilterDirector responseDirector = handler.handleResponse(request, response);

      assertEquals(
          "Auth component must identify proxy auth failures",
          HttpStatusCode.NOT_IMPLEMENTED,
          responseDirector.getResponseStatus());
    }