ten small Python programs

[Steve Howell]

--- Steven Bethard <steven.bethard at gmail.com> wrote:

> I think I would rewrite the current unit-testing
> example to use the 
> standard library unittest module::
> 
>      # Let's write reusable code, and unit test it.
>      def add_money(amounts):
>          # do arithmetic in pennies so as not to
> accumulate float errors
>          pennies = sum([round(int(amount * 100)) for
> amount in amounts])
>          return float(pennies / 100.0)
>      import unittest
>      class TestAddMoney(unittest.TestCase):
>          def test_float_errors(self):
>              self.failUnlessEqual(add_money([0.13,
> 0.02]), 0.15)
>              self.failUnlessEqual(add_money([100.01,
> 99.99]), 200)
>              self.failUnlessEqual(add_money([0,
> -13.00, 13.00]), 0)
>      if __name__ == '__main__':
>          unittest.main()
> 
> I believe I've still kept it to 13 lines.
> 

I approve this change, although in a sense, it's
harder for a Python newbie, because it introduces
inheritance a little earlier than I would have liked.

FWIW I'm in the minority (I think) of people that
prefer roll-your-own testing, but I don't want to
argue that, because I think it mostly comes down to
personal preference.

I'll only defend my position by posting this link,
which suggests that roll-your-own even has validity in
an educational setting:

http://www.elkner.net/jeff/testFirst/index.html


> P.S. The "right" way to add money is using the
> decimal module, but I 
> couldn't think of a better example.

Agreed.  Maybe somebody else will come up with
something more creative, but I'm happy enough with our
current version.


       
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