public void GivenASalePricing_Validate_ShouldNotHaveAValidationError()
        {
            // Arrange.
            var salePricing = new SalePricing
            {
                SalePrice     = 1234,
                SalePriceText = "Contact agent"
            };

            // Act & Assert.
            _validator.ShouldHaveChildValidator(listing => listing.Pricing, typeof(SalePricingValidator));
            _validator.ShouldNotHaveValidationErrorFor(listing => listing.Pricing, salePricing);
        }