public async Task ExistsAsync_should_return_false_if_email_invalid()
        {
            var sut    = new CustomerEmailsService(_fixture.Database);
            var result = await sut.ExistsAsync(Guid.NewGuid().ToString());

            result.Should().BeFalse();
        }
        public async Task ExistsAsync_should_return_true_if_email_valid()
        {
            var sut = new CustomerEmailsService(_fixture.Database);

            var email      = Guid.NewGuid().ToString();
            var customerId = Guid.NewGuid();
            await sut.CreateAsync(email, customerId);

            var result = await sut.ExistsAsync(email);

            result.Should().BeTrue();
        }