tests/test-check-pyflakes.t

keepalive: switch from thread to threading module

The thread module in py3 is renamed to _thread, but we can use
 the high level threading module instead.

#require test-repo pyflakes hg10

  $ . "$TESTDIR/helpers-testrepo.sh"
  $ cd "`dirname "$TESTDIR"`"

run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)

  $ hg locate 'set:**.py or grep("^#!.*python")' 2>/dev/null \
  > | xargs pyflakes 2>/dev/null | "$TESTDIR/filterpyflakes.py"
  tests/filterpyflakes.py:61: undefined name 'undefinedname'