public void TestValidSubtractionOfTwoPositiveNumbers()
        {
            var subtraction = new Subtraction();
            var result = subtraction.Apply(1339, 2);
            var expected = 1337;

            Assert.AreEqual(expected, result);
        }
        public void TestValidSubtractionOfTwoNegativeNumbers()
        {
            var subtraction = new Subtraction();
            var result = subtraction.Apply(-3, 2);
            var expected = -5;

            Assert.AreEqual(expected, result);
        }