public void ContainsDateShouldReturnTrueWhenIntervalIsInfinite(IDateInterval interval, DateTime date)
        {
            var result = interval.ContainsDate(date);

            Assert.True(result);
        }
        public void ContainsDateShouldReturnFalseWhenNullIsProvided(IDateInterval interval)
        {
            var result = interval.ContainsDate(null);

            Assert.False(result);
        }