The following is a TDD Kata- an exercise in coding, refactoring and test-first.
Try not to read ahead. Do one task at a time. The trick is to learn to work incrementally. Make sure you only test for correct inputs. there is no need to test for invalid inputs for this kata
- Create a simple String calculator with a method int Add(string numbers)
- The method can take 0, 1 or 2 numbers, and will return their sum (for an empty string it will return 0) for example “” or “1” or “1,2”
- Start with the simplest test case of an empty string and move to 1 and two numbers
- Remember to solve things as simply as possible so that you force yourself to write tests you did not think about
- Remember to refactor after each passing test
- Allow the Add method to handle an unknown amount of numbers
- Allow the Add method to handle new lines between numbers (instead of commas).
- the following input is ok: “1\n2,3” (will equal 6)
- the following input is NOT ok: “1,\n” (not need to prove it - just clarifying)
- Support different delimiters
- to change a delimiter, the beginning of the string will contain a separate line that looks like this: “//[delimiter]\n[numbers…]” for example “//;\n1;2” should return three where the default delimiter is ‘;’ .
- the first line is optional. all existing scenarios should still be supported
- Calling Add with a negative number will throw an exception “negatives not allowed” - and the negative that was passed.if there are multiple negatives, show all of them in the exception message