This whole refactoring project grew out of the fact that Chris and I were looking for somewhere to put common helpers for package testing. Specfically, I wrote a heap of helpers for test_runpy that I wanted to use for the new pkgutil tests.

The short term hack (because 3.3 was imminent) is that a couple of the pkgutil tests are *in* test_runpy, not because they belong there, but so they can use those helper utilities. We knew when we did it that wasn't a viable long term solution, but we didn't have a good place to put the helpers so test_pkgutil could get at them - they're packaging specific, so junking up test.support with them would be bad, and we knew from experience that a separate helper module (like script_helper) sucked for discoverability.

So, the idea of making test.support a subpackage was born. The current contents of support.py go into the new __init__.py, script_helper moves there to make it more discoverable, and the utilities for packaging tests can move out of test_runpy and into test.support.pkg_helper. Both script_helper and pkg_helper can also be easily covered in the docs under the existing "test.support" caveat.

We didn't start down this road on a whim - we did it because we ran up hard against a clear and obvious problem in the structure of the test suite's support modules.