public void FindNextBiggerNumber3()
        {
            FindNextBiggerNumber fnbn = new FindNextBiggerNumber();

            Assert.AreEqual(3462345, fnbn.FNBN(3456432));
        }
        public void FindNextBiggerNumber1()
        {
            FindNextBiggerNumber fnbn = new FindNextBiggerNumber();

            Assert.AreEqual(21, fnbn.FNBN(12));
        }
        public void FindNextBiggerNumber2()
        {
            FindNextBiggerNumber fnbn = new FindNextBiggerNumber();

            Assert.AreEqual(1241233, fnbn.FNBN(1234321));
        }