public void GetContactTypes_NoContactTypesFound_ReturnsContactTypes(
            [Frozen] Mock <IReferenceDataApiClient> referenceDataApiClient,
            ReferenceDataService sut
            )
        {
            //Arrange
            referenceDataApiClient.Setup(x => x.GetContactTypesAsync())
            .ReturnsAsync((List <ContactType>)null);

            //Act
            Func <Task> func = async() => await sut.GetContactTypesAsync();

            //Assert
            func.Should().Throw <ArgumentNullException>()
            .WithMessage("Value cannot be null. (Parameter 'contactTypes')");
        }
        public async Task GetContactTypes_ContactTypesFound_ReturnsContactTypes(
            [Frozen] Mock <IReferenceDataApiClient> referenceDataApiClient,
            List <ContactType> contactTypes,
            ReferenceDataService sut
            )
        {
            //Arrange
            referenceDataApiClient.Setup(x => x.GetContactTypesAsync())
            .ReturnsAsync(contactTypes);

            //Act
            var response = await sut.GetContactTypesAsync();

            //Assert
            response.Count.Should().Be(3);
        }