public void SubtractionTest()
        {
            var obj = new ImportantClass();

            Assert.AreEqual(obj.GetNum(), 0);
            obj.SubFromNum(-13);
            Assert.AreEqual(obj.GetNum(), 13);
        }
        public void AddSubTest()
        {
            var obj = new ImportantClass();

            Assert.AreEqual(obj.GetNum(), 0);
            obj.SubFromNum(13);
            obj.AddToNum(13);
            Assert.AreEqual(obj.GetNum(), 0);
        }