public async void ByName_Not_Exists()
        {
            var mock = new ServiceMockFacade <IProductCategoryRepository>();

            mock.RepositoryMock.Setup(x => x.ByName(It.IsAny <string>())).Returns(Task.FromResult <ProductCategory>(null));
            var service = new ProductCategoryService(mock.LoggerMock.Object,
                                                     mock.RepositoryMock.Object,
                                                     mock.ModelValidatorMockFactory.ProductCategoryModelValidatorMock.Object,
                                                     mock.BOLMapperMockFactory.BOLProductCategoryMapperMock,
                                                     mock.DALMapperMockFactory.DALProductCategoryMapperMock,
                                                     mock.BOLMapperMockFactory.BOLProductSubcategoryMapperMock,
                                                     mock.DALMapperMockFactory.DALProductSubcategoryMapperMock);

            ApiProductCategoryResponseModel response = await service.ByName(default(string));

            response.Should().BeNull();
            mock.RepositoryMock.Verify(x => x.ByName(It.IsAny <string>()));
        }