PermissionError: [WinError 32] during unittests

[toomanybrians]

I'm adding this because it's something that happens occasionally, though I haven't personally seen it, but it's been seen by two users in the forum.

Sometimes when running all the mpf-mc unittests, there's an error like this:

PermissionError: [WinError 32] The process cannot access the file because it is being used by another process: 'C:\\Users\\winli\\.kivy\\None\\kivy_16-12-15_5.txt'

Instances of this: https://groups.google.com/forum/#!search/%22winerror$2032%22%7Csort:relevance/mpf-users/-aY4W_t2KME/m56gshUKDAAJ https://groups.google.com/forum/?utm_medium=email&utm_source=footer#!msg/mpf-users/zxPVoV2VPrM/-sUCpIa8FgAJ

I don't know enough about how this works to know about a solution. I assume it's something like the kivy log file not being closed between test runs? I don't know if this is something we can fix in our test setup or teardown.. check for open handles and wait or something?