public void GetHashCode_Same()
        {
            // arrange
            var p = new Rational.Rational(4, -2);
            var q = new Rational.Rational(-2, 1);

            // assert
            Assert.Equal(p.GetHashCode(), q.GetHashCode());
        }
        public void GetHashCode_Different()
        {
            // arrange
            var p = new Rational.Rational(4, 2);
            var q = new Rational.Rational(-2, 1);

            // assert
            Assert.NotEqual(p.GetHashCode(), q.GetHashCode());
        }