run-tests: fix race condition
Before this patch, it was possible for run-tests to crash on a race condition.
The race condition happens in the following case:
- the last test finishes and calls: done.put(None)
- the context switches to the main thread that clears the channels list
- the context switches to the last test mentioned above, it tries to access
channels[channel] and crashes
This happened to me while running run-tests.
This patch fixes the issue by clearing the channel before considering that the
test is done.
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.