Learn to use Test Driven Development to create a program.
This kata was created by Roy Osherove and is designed to help you learn TDD coding and refactoring.
Try not to read ahead – do one task at a time. Work incrementally.
- Create a String calculator with a method int Add(string numbers)
- The method can take 0, 1, or 2 numbers and will return their sum.
- An empty string will return 0.
- Example inputs:
“”, “1”, or “1,2” - Start with the simplest test case of an empty string. Then 1 number. Then 2 numbers.
- Remember to solve things as simply as possible, forcing yourself to write tests for things you didn’t think about.
- Remember to refactor after each passing test.
- Allow the Add method to handle an unknown number of arguments/numbers.
- Allow the Add method to handle new lines between numbers (instead of commas).
- Example:
“1\n2,3”should return 6. - Example:
“1,\n”is invalid, but you don’t need a test for this case. - Only test correct inputs – there is no need to deal with invalid inputs for this kata.
- Example:
- Calling Add with a negative number will throw an exception “Negatives not allowed: “ listing all negative numbers that were in the list of numbers.
- Example
“-1,2”throws “Negatives not allowed: -1” - Example
“2,-4,3,-5”throws “Negatives not allowed: -4,-5”
- Example
- Numbers bigger than 1000 should be ignored.
- Example:
“1001,2”returns 2
- Example:
- Allow the Add method to handle a different delimiter:
- To change the delimiter, the beginning of the string will contain a separate line that looks like this:
“//[delimiter]\n[numbers]” - Example:
“//;\n1;2”should return 3 (the delimiter is ;) - This first line is optional; all existing scenarios (using , or \n) should work as before.
- To change the delimiter, the beginning of the string will contain a separate line that looks like this: