public void RationnalNormalizeTest()
        {
            Rationnal r = new Rationnal(420, -840);
            string    ExpectedResult = "-1/2";

            Assert.AreEqual(ExpectedResult, r.ToString());
        }
        public void RationnalAdditionTest()
        {
            Rationnal r1             = new Rationnal(1, 2),
                      r2             = new Rationnal(-2, 7);
            Rationnal CurrentResult  = r1 + r2;
            string    ExpectedResult = "3/14";

            Assert.AreEqual(ExpectedResult, CurrentResult.ToString());
        }