"""
Introduction to Test-driven Development

We're going to implement a simple algorithm using the "Test-driven Development" methodology. 

TDD works like this:

1. Never write a single line of code unless you have a failing automated test.
2. Eliminate duplication.

We're going to concentrate on step 1. 

Interestingly, it turns out that the most important question in software development (from my POV, anyway) is:

    How do you know when you're done? 

TDD offers an answer: "When all your tests pass."

What's a test? 





http://en.wikipedia.org/wiki/Test-driven_development
"""
def intlist(n):
    text = str(n)   # in order to "split up" the integer we have to treat it as a string
    digits = list(text)
    integers = [int(x) for x in digits] #  now convert them back to digits.
    return integers



def test_adder(n):
    pass


def test_intlist(n):
    return assert intlist(123) == [1,2,3]


print intlist(123)