StringCalculator - TDD Kata with Spock

This TDD Kata is about creating a StringCalculator.

Rules

• Do one step after another
• Use the simple TDD cycle:
  1. Write failing test
  2. Implement code as simple as the test succeeds
  3. Refactor your code if necessary
  4. Continue with first step
• Special rule for this TDD Kata: Use Spock for writing tests.

String Calculator

• 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”

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

Handle negative numbers

• 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

Note

The example can also be found at http://osherove.com/tdd-kata-1/