AdderKata.CalculatorTests.It_Says_Which_Inputs_Were_Invalid C# (CSharp) Method

        public void It_Says_Which_Inputs_Were_Invalid()
        {
            //--Arrange
            var calculator = new Calculator();
            var input = "-6,-15";

            //--Act/Assert
            Exception ex = Assert.Throws<ArgumentException>(() => calculator.Add(input));
            Assert.AreEqual("negatives not allowed -6 -15", ex.Message);
        }