[Python-Dev] fixing tests on windows

[Tim Golden]

[re tests which fail because something's holding a file
open with SHARE_DELETE]

Well I've tried my best, but I can't come up with a solution
which guarantees to overcome this obstacle. I set up a fairly
aggressive directory watcher which, when it sees a test file
being created, takes a SHARE_DELETE handle on it and releases
it immediately. (Guessing that this is what the other apps
are doing).

Running the test suite from HEAD, this generates all manner
of access-denied type errors as per the original output.

I used tempfile to generate a random TESTFN in the current directory
rather than the static @test. And implemented the rename-shim
discussed previously, renaming to a different random name, courtesy
of mktemp. With those in place, most tests run without error. But
I'm still getting errors in the same sort of areas which Steven B
originally reported.

The one error I can't see a way round is the access denied (which
manifests as Permission Error) which is the documented result of
attempting to open a file with a pending delete -- ie the delete
succeeded but hasn't completed yet.

An additional complication is that there are hundreds of
instances throughout the tests where the test simply calls
os.unlink/os.remove to undo the test file. To have some more
robust central deletion I had to go through and update 68 tests.

I'll keep trying, but in the current state I'm not convinced
the situation's improved enough for me to bother uploading
a patch.

TJG