public async Task GetPublishedProviderErrors_ReturnsNotFound_WhenUnderlyingAPIReturnsNotFound()
        {
            _publishingApiClient
            .GetPublishedProviderErrors(ValidSpecificationId)
            .Returns(new ApiResponse <IEnumerable <string> >(HttpStatusCode.NotFound));

            IActionResult result = await _publishController.GetSpecProviderErrors(ValidSpecificationId);

            result.Should().BeOfType <NotFoundObjectResult>();
        }