testing: allow Hypothesis to enable extensions
This adds support for testing extensions, including both tests
that extensions don't change behaviour and test for specific
commands.
We use the precondition system to determine what commands are
available to us. If we never use any commands enabled by an
extension then that extension is *skippable* and should not
have changed the behaviour of the test. We thus rerun the test
with an environment variable which is designed to turn off the
extension.
#!/usr/bin/env python
#
# check-py3-compat - check Python 3 compatibility of Mercurial files
#
# Copyright 2015 Gregory Szorc <gregory.szorc@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import, print_function
import ast
import sys
def check_compat(f):
"""Check Python 3 compatibility for a file."""
with open(f, 'rb') as fh:
content = fh.read()
# Ignore empty files.
if not content.strip():
return
root = ast.parse(content)
futures = set()
haveprint = False
for node in ast.walk(root):
if isinstance(node, ast.ImportFrom):
if node.module == '__future__':
futures |= set(n.name for n in node.names)
elif isinstance(node, ast.Print):
haveprint = True
if 'absolute_import' not in futures:
print('%s not using absolute_import' % f)
if haveprint and 'print_function' not in futures:
print('%s requires print_function' % f)
if __name__ == '__main__':
for f in sys.argv[1:]:
check_compat(f)
sys.exit(0)