private async void BeUniqueByName_Create_Not_Exists()
        {
            Mock <ICountryRegionRepository> countryRegionRepository = new Mock <ICountryRegionRepository>();

            countryRegionRepository.Setup(x => x.ByName(It.IsAny <string>())).Returns(Task.FromResult <CountryRegion>(null));
            var validator = new ApiCountryRegionRequestModelValidator(countryRegionRepository.Object);

            await validator.ValidateCreateAsync(new ApiCountryRegionRequestModel());

            validator.ShouldNotHaveValidationErrorFor(x => x.Name, "A");
        }