public void GetSpecificationById_GivenNullOrEmptyUrl_ThrowsArgumentException()
        {
            //Arrange
            SpecificationsRepository specificationsRepository = CreateSpecificationsRepository();

            //Act
            Func <Task> test = async() => await specificationsRepository.GetSpecificationSummaryById("");

            //Assert
            test
            .Should().ThrowExactly <ArgumentNullException>();
        }
        async public Task GetSpecificationById_GivenSpecificationId_CallsWithCorrectUrl()
        {
            //Arrange
            const string specificationId = "spec-id";

            ISpecificationsApiClientProxy clientProxy = CreateApiClientProxy();

            SpecificationsRepository specificationsRepository = CreateSpecificationsRepository(clientProxy);

            //Act
            await specificationsRepository.GetSpecificationSummaryById(specificationId);

            //Assert
            await
            clientProxy
            .Received(1)
            .GetAsync <SpecificationSummary>(Arg.Is($"specs/specification-summary-by-id?specificationId={specificationId}"));
        }