tests/readlink.py

tests: add explicit coverage for update_hash_refs from rewriteutil

I couldn't find any evidence this is covered by tests in core (but there's a
good chance I missed it). We've seen a cute bug in that code, but first
let's just cover the cases that work correctly.

Differential Revision: https://phab.mercurial-scm.org/D11231

#!/usr/bin/env python3

from __future__ import absolute_import, print_function

import errno
import os
import sys

for f in sys.argv[1:]:
    try:
        print(f, '->', os.readlink(f))
    except OSError as err:
        if err.errno != errno.EINVAL:
            raise
        print(f, '->', f, 'not a symlink')

sys.exit(0)