InsaneWookie / tdd-kata-1-string-calculator

TDD Kata - String Calculator [http://osherove.com/kata]

Before you start:

• TRY NOT TO READ AHEAD
• DO ONE TASK AT A TIME
• THE TRICK IS TO LEARN TO WORK INCREMENTALLY
• TEST FIRST
• REMEMBER TO REFACTOR AFTER EACH TEST PASSES

Create a class with a single method, add, which receives a string and returns an integer. This is the class we will be testing.

1. Return a zero for an empty string

For example

"" == 0

2. If a single number is received, return that number

For example

"1" == 1

3. If two numbers are received, separated by a comma, return the sum of those numbers

For example

"1,2" == 3

4. Handle receiving any amount of numbers

5. Handle new lines as well as commas between numbers

The following input is ok:

"1\n2,3" == 6

The following is INVALID input, so do not expect it:

"1,\n"

6. Support different delimiters between numbers

To change a delimiter, the beginning of the string will contain a separate line that looks like this:

"//[delimiter]\n[numbers...]"

For example, since the default delimiter is ‘;’:

"//;\n1;2" == 3

Note: All existing scenarios and tests should still be supported

7. Throw an exception if a negative number is included, the exception message should contain the negative number that was included

8. If there are multiple negative numbers, ensure all of them appear in the exception message

9. Numbers bigger than 1000 should be ignored

For example:

"1001,2" == 2

10. Support delimiters of any length

A multi-character delimiter will be surrounded by square brackets, formatted as:

"//[delimiter]\n"

For example:

"//[***]\n1***2***3" == 6

11. Allow multiple delimiters

Multiple delimiters will be surrounded by square brackets one after another, formatted as:

"//[delim1][delim2]\n"

For example:

"//[*][%]\n1*2%3" == 6

12. Refactoring

You reached the end of the exercise. Hopefully you have been refactoring as you go; but consider taking some time to reflect on how you might improve the maintainability or understandability of your code.