tests: do not use system hg if it does not have "files" command Ancient hg does not have "hg files" so test-check-*.t will fail with "unknown command 'files'": $ hg files hg: unknown command 'files' $ hg --version Mercurial Distributed SCM (version 2.6.2) Test "hg files" and give up using syshg if it does not have "files" command.

from __future__ import absolute_import

from mercurial.i18n import _
from mercurial import (
        changegroup,
        error,
        extensions
    )

def abort(orig, *args, **kwargs):
    raise error.Abort(_('this is an exercise'))

def uisetup(ui):
    extensions.wrapfunction(changegroup, 'getbundler', abort)