While most test suites are a tree with test_*.py files, there are cases where being able to define the discovery for a subtree in the package __init__.py file comes handy.

A poc implementation is available at 
http://bazaar.launchpad.net/~canonical-isd-qa/selenium-simple-test/trunk/view/head:/src/sst/tests/test_loader.py 

http://bazaar.launchpad.net/~canonical-isd-qa/selenium-simple-test/trunk/view/head:/src/sst/loader.py

It allows test writers to define their own discovery when needed (including a specific edge case for the project mentioned above: test scripts that should not be imported at load time).

It also addresses http://bugs.python.org/issue16662

This is a duplicate of 16662

Well, spoke with vila on IRC. I content it's a duplicate because if load_tests in __init__ kicks in and supercedes discovery, I believe this bug would not be needed.

The linked code does something different.  I believe the title of this issue is incorrect for the implicitly suggested enhancement.  I also suspect the suggested enhancement (to the extent that I understand it) is not ripe for stdlib inclusion, but I'll leave that up to Michael.

The load_tests protocol is already the intended way for test writers to customize discovery. The problem, as issue 16662 states, is that load_tests is not invoked for packages by default. Fixing that is the right fix.

I'm rejecting this issue in favour of 16662.

> The linked code does something different.

Right, it addressed other issues encountered in that project:
1 - the need for different paterns for files and directories (http://bugs.python.org/issue16662),
2 - handling import errors at load time (http://bugs.python.org/issue7559 as Robert told me),
3 - changing discovery policy at package level
4 - not importing test files (project specific)

The most blocking issue in that project was that there was no way to address (3). If that's fixed (and (1) as well) with http://bugs.python.org/issue16662, I'm fine with that, I'll be able to build the specifics for that project on top of it.