On Sat, Jan 24, 2015 at 4:21 AM, Chris Barker <chris.barker@noaa.gov> wrote:
If you wanted to make that check more widely available, why not simply make it into a full-fledged function rather than an assertion?
That would be an option, but I don't think the one in unittest is the right test anyway -- its focus on on number of decimal digits after the decimal place is not generally useful. (that would make some sense for the Decimal type...)
And if it's not suitable for that purpose, why does this PEP not propose updating the unittest assertion to use the new function?
well, for backward compatibility reasons, I had just assumed it was off the table -- or a long, painful road anyway. And the unitest is very vested in it's OO structure -- would we want add free-form functions to it?
Updating the assertion to use the new function would be a matter of tweaking the implementation of unittest's assertAlmostEqual() to now call this function and assert that it returns True. The OO structure of unittest wouldn't be affected; just the exact definition of one particular assertion. I'd say that's a point worth mentioning in the PEP. Conceptually, this is going to do the same thing; yes, it's a change of definition, but obviously this won't be done in a point release anyway. It would make reasonable sense to sync them up. Alternatively, if you choose not to have that as part of the proposal, it would be worth adding a word or two of docs to unittest stating that assertAlmostEqual is not the same as is_close_to (and/or add "assertCloseTo" which would use it), as the existing implementation is all about absolute difference. ChrisA