tests/test-check-pyflakes.t

branchmap: factorise access to changelog in updatebranchcache

This prepares merge of `updatebranchcache` and `_branchtags`.

  $ "$TESTDIR/hghave" pyflakes || exit 80
  $ cd "`dirname "$TESTDIR"`"
  $ pyflakes mercurial hgext 2>&1 | "$TESTDIR/filterpyflakes.py"
  hgext/inotify/linux/__init__.py:*: 'from _inotify import *' used; unable to detect undefined names (glob)