Skipping decorators in unit tests

[Cameron Simpson]

On 10Oct2013 19:44, Ned Batchelder <ned at nedbatchelder.com> wrote:
> On 10/10/13 6:12 PM, Cameron Simpson wrote:
> >Speaking for myself, I would be include to recast this code:
> >
> >   @absolutize
> >   def addition(a, b):
> >       return a + b
> >
> >into:
> >
> >   def _addition(a, b):
> >       return a + b
> >
> >   addition = absolutize(_addition)
> >
> >Then you can unit test both _addition() and addition(). [...]
> 
> I have to admit I'm having a hard time understanding why you'd need
> to test the undecorated functions.  After all, the undecorated
> functions aren't available to anyone.  All that matters is how they
> behave with the decorators.

If the undecorated function is buggy, the decorated function will
be buggy. But the bug will be harder to resolve, and if you're
especially lucky the decorator will often-but-not-always conceal
the bug in the inner function.

Wanting to test the core function is perfectly reasonable. You can in
principle write simpler and more direct tests of the core function.

Having an error report that points directly at an error instead of
an error report that points at some outer dysfunction (i.e. "somewhere
deep inside here something is broken") is highly desirable in
general, and therefore also in a test suite.

Cheers,
-- 
Cameron Simpson <cs at zip.com.au>

They shouldn't get any new nuclear weapons until they've used the ones
they've got.    - Murff