+def str_keep_locator(s):
+ return '{}+{}'.format(hashlib.md5(s if isinstance(s, bytes) else s.encode()).hexdigest(), len(s))
+
+@contextlib.contextmanager
+def redirected_streams(stdout=None, stderr=None):
+ if stdout == StringIO:
+ stdout = StringIO()
+ if stderr == StringIO:
+ stderr = StringIO()
+ orig_stdout, sys.stdout = sys.stdout, stdout or sys.stdout
+ orig_stderr, sys.stderr = sys.stderr, stderr or sys.stderr
+ try:
+ yield (stdout, stderr)
+ finally:
+ sys.stdout = orig_stdout
+ sys.stderr = orig_stderr
+
+
+class VersionChecker(object):
+ def assertVersionOutput(self, out, err):
+ if sys.version_info >= (3, 0):
+ self.assertEqual(err.getvalue(), '')
+ v = out.getvalue()
+ else:
+ # Python 2 writes version info on stderr.
+ self.assertEqual(out.getvalue(), '')
+ v = err.getvalue()
+ self.assertRegex(v, r"[0-9]+\.[0-9]+\.[0-9]+$\n")