tests/readlink.py

tests: test a variety of cache invariants

We've historically had a problem maintaining the expected invariants
on our caches, especially when introducing new caches. This tests
documents the invariants and exercises them across most of our
existing cache files.

#!/usr/bin/env python

import errno, os, 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, 'not a symlink'

sys.exit(0)