public void GetGCDTest()
        {
            GreatestCommonDivisor gcd = new GreatestCommonDivisor();
            int result = gcd.GetGCDbyEvclideAl(15, 0);

            Assert.AreEqual(result, 15);
            result = gcd.GetGCDbyEvclideAl(15, -5);
            Assert.AreEqual(result, 5);

            result = gcd.GetGCDSteinAl(15, 0);
            Assert.AreEqual(result, 15);
            result = gcd.GetGCDSteinAl(15, -5);
            Assert.AreEqual(result, 5);
        }