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