public void SenderWithValidNameIsValid()
        {
            var alert = new Alert();
            alert.Sender = "*****@*****.**";

            var senderValidator = new SenderRequiredValidator(alert);
            Assert.True(senderValidator.IsValid);
            Assert.Equal(0, senderValidator.Errors.Count());
        }
        public void SenderWithNullNameIsInvalid()
        {
            var alert = new Alert();
            alert.Sender = null;

            var senderValidator = new SenderRequiredValidator(alert);
            Assert.False(senderValidator.IsValid);
            Assert.Equal(typeof(SenderRequiredError), senderValidator.Errors.ElementAt(0).GetType());
        }