This TDD Kata is about creating a StringCalculator.
- Do one step after another
- Use the simple TDD cycle:
- Write failing test
- Implement code as simple as the test succeeds
- Refactor your code if necessary
- Continue with first step
- Special rule for this TDD Kata: Use Spock for writing tests.
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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
- the following input is ok: “1\n2,3” (will equal 6)
- the following input is NOT ok: “1,\n”
- 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
The example can also be found at http://osherove.com/tdd-kata-1/