Running just the two tests fails on windows also, with all three versions. For 2.7, test_ttk_guionly is skipped with "test_ttk_guionly skipped -- tk not available: Can't find a usable init.tcl in the following directories:. This in spite of the fact that the idle test just found init.tcl and that the ttk test passes without the idle test running first. This is relatively recent.

Does the test runner not delete modules as they are finished?

I am rebuilding python and will try tests again. If problem persists and patch solves it, I will go ahead and apply.