Making the `nosetests` script select folder by Python version

Question

I used to have this in my setup.cfg file:

[nosetests]
where=test_python_toolbox

But now I'm supporting Python 2 and Python 3 by supplying two parallel codebases, one in the source_py2 folder and one in the source_py3 folder. setup.py knows how to check the Python version and choose the correct one. Problem is, I don't know how to make nosetests, when invoked in the repo root, select the correct folder.

I could have this:

[nosetests]
where=source_py2/test_python_toolbox

But then tests would work only for Python 2. I want them to work for both versions.

I could launch nosetests with a flag, but I'd rather not.

Answer 1

[nosetests]
where=source_py2/test_python_toolbox
py3where=source_py3/test_python_toolbox

Answer 2

Instead of using where which is deprecated, use tests and specify multiple tests:

[nosetests]
tests=source_py2/test_python_toolbox, source_py3/test_python_toolbox

This will run both set of tests. For each test, at the very top, before language specific features are in place, add the selection criteria for running tests. For example, for source_py3 tests add:

import sys
from unittest import SkipTest

if sys.version_info < (3, 0):
    raise SkipTest("must use python 3.0 or greater")

With python2.6 nose you will get:

S
----------------------------------------------------------------------
Ran 1 test in 0.001s

OK (SKIP=1)

for each test module that has it. The ugly aspect is that you have to inject this code in every test case.

Answer 3

tox can do that via multiple environment specifications, and the changedir option (just override that per Python version).