public void NotEquals()
        {
            var first = new DateRange(this.date1900, this.date2000);
            var second = new DateRange(this.date1900, this.date1950);

            Assert.IsTrue(first != second, "Operator inequality");
            Assert.IsFalse(first.Equals(second), "Method inequality");
        }
        public void Equals()
        {
            var first = new DateRange(this.date1900, this.date2000);
            var second = new DateRange(this.date1900, this.date2000);

            Assert.IsTrue(first == second, "Operator equality");
            Assert.IsTrue(first.Equals(second), "Method equality");
        }