public void checksub() { int a = -4; int b = 4; int expected = a - b; int actual = obj.sub(a, b); Assert.AreEqual(actual, expected, 0, "Result is wrong"); int a1 = int.MaxValue; int b1 = int.MinValue; Assert.ThrowsException <System.OverflowException>(() => obj.sub(a1, b1)); int a2 = int.MaxValue; int b2 = -23; Assert.ThrowsException <System.OverflowException>(() => obj.sub(a2, b2)); int a3 = int.MinValue; int b3 = 2; Assert.ThrowsException <System.OverflowException>(() => obj.sub(a3, b3)); }