# Python Fizz Buzz, Acceptance Unit test

OK, maybe crazy overkill and a little silly, but why not? Here's a Python FizzBuzz Acceptance Test:

import unittest
from fizzbuzzmodule import fizzbuzz

class FizzBuzzAcceptanceTestCase(unittest.TestCase):
'''
Test that fizzbuzz(int) returns int
unless multiple of 3 (then returns 'fizz')
multiple of 5 (then returns 'buzz')
multiple of both (then returns 'fizzbuzz')
'''
'''
test that an integer >= 0 not evenly divisible
by three or five returns the same
'''
self.assertEqual(fizzbuzz(1), 1)
self.assertEqual(fizzbuzz(2), 2)
self.assertEqual(fizzbuzz(4), 4)
self.assertEqual(fizzbuzz(7), 7)
self.assertEqual(fizzbuzz(998), 998)
def test_fizz(self):
'''evenly divisible by 3 returns fizz'''
self.assertEqual(fizzbuzz(3), 'fizz')
self.assertEqual(fizzbuzz(6), 'fizz')
self.assertEqual(fizzbuzz(111), 'fizz')
self.assertEqual(fizzbuzz(999), 'fizz')
def test_buzz(self):
'''evenly divisible by 5 returns buzz'''
self.assertEqual(fizzbuzz(5), 'buzz')
self.assertEqual(fizzbuzz(10), 'buzz')
self.assertEqual(fizzbuzz(20), 'buzz')
self.assertEqual(fizzbuzz(500), 'buzz')
def test_fizz_buzz(self):
'''evenly divisible by 3 and 5 returns fizzbuzz'''
self.assertEqual(fizzbuzz(15), 'fizzbuzz')
self.assertEqual(fizzbuzz(30), 'fizzbuzz')
self.assertEqual(fizzbuzz(45), 'fizzbuzz')
self.assertEqual(fizzbuzz(600), 'fizzbuzz')

# def test_zero(self):
# self.assertEqual(fizzbuzz(0), 'fizzbuzz') #??????

def main():
unittest.main()

if __name__ == '__main__':
main()


Typed up a little implementation that passes these tests:

def fizzbuzz(number):
'''
if number divisible by 3 return 'fizz';
5, 'buzz'; both, fizzbuzz
else return number
'''
if not number % 3:
if not number % 5:
return 'fizzbuzz'
else:
return 'fizz'
if not number % 5:
return 'buzz'
return number

def main():
for i in range(1, 101):
print fizzbuzz(i)


And when I run the tests:

>>> unittest.main()
....
----------------------------------------------------------------------
Ran 4 tests in 0.002s

OK


And my question is, how would you augment the above? Would you find it useful to run this test on someone's code? Does it clearly define a clean API? Would it be preferable to return a consistent type instead of strings or ints?

Should I have done this differently? Have I not considered any edge or corner cases?

• you should remove the code golf part, or post it on the Code Golf Stack Site.
– Malachi
Jan 10, 2014 at 6:04
• No code golf! :) Jan 10, 2014 at 6:06

For something so simple, it might be less overkill to use the doctest module. Write the expected calls and outputs in the docstring, then run python -m doctest -v fizzbuzzmodule.py. There's no need to write a separate class.

I've written one of the tests to ensure that the function also works when called with decreasing arguments.

As for the function itself, I believe that the code reads better if you write number % 3 == 0 instead of not number % 3. I would also use a conditional expression, but that's just a matter of personal preference.

def fizzbuzz(number):
'''
if number divisible by 3 return 'fizz';
5, 'buzz'; both, fizzbuzz
else return number

>>> fizzbuzz(1)
1
>>> fizzbuzz(2)
2
>>> fizzbuzz(3)
'fizz'
>>> fizzbuzz(4)
4
>>> fizzbuzz(5)
'buzz'
>>> fizzbuzz(15)
'fizzbuzz'
>>> [fizzbuzz(i) for i in range(31, 20, -1)]
[31, 'fizzbuzz', 29, 28, 'fizz', 26, 'buzz', 'fizz', 23, 22, 'fizz']
'''
if number % 3 == 0:
return 'fizzbuzz' if (number % 5 == 0) else 'fizz'
if number % 5 == 0:
return 'buzz'
return number