public void whenNewLineIsUsedBetweenNumbersThenReturnValuesAreTheirSums()
 {
     Assert.AreEqual(3 + 6 + 15, StringCalculator5.Add("3,6\n15"));
 }
 public void when2NumbersAreUsedThenNoExceptionIsThrown()
 {
     Assert.DoesNotThrow(() => StringCalculator5.Add("1,2"));
 }
 public void whenAnyNumberOfNumbersIsUsedThenReturnValueAreTheirSums()
 {
     Assert.AreEqual(3 + 6 + 15 + 18 + 46 + 33, StringCalculator5.Add("3,6,15,18,46,33"));
 }
 public void whenTwoNumbresAreUsedThenReturnValueIsTheirSum()
 {
     Assert.AreEqual(3 + 6, StringCalculator5.Add("3,6"));
 }
 public void whenOneIsUsedThenReturnValueIsThatSameNumber()
 {
     Assert.AreEqual(3, StringCalculator5.Add("3"));
 }
 public void whenEmptyStringIsUsedThenReturnValueIs0()
 {
     Assert.AreEqual(0, StringCalculator5.Add(""));
 }
 public void whenNonNumberIsUsedThenExceptionIsThrown()
 {
     Assert.Throws(typeof(FormatException), () => StringCalculator5.Add("1,x"));
 }