tests/md5sum.py

tests: better testing of loaded certificates

Tests were failing on systems like RHEL 7 where loading the system
certificates results in CA certs being reported to Python. We add
a feature that detects when we're able to load *and detect* the
loading of system certificates. We update the tests to cover the
3 scenarios:

1) system CAs are loadable and detected
2) system CAs are loadable but not detected
3) system CAs aren't loadable

#!/usr/bin/env python
#
# Based on python's Tools/scripts/md5sum.py
#
# This software may be used and distributed according to the terms
# of the PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2, which is
# GPL-compatible.

import sys, os

try:
    from hashlib import md5
except ImportError:
    from md5 import md5

try:
    import msvcrt
    msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
    msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
except ImportError:
    pass

for filename in sys.argv[1:]:
    try:
        fp = open(filename, 'rb')
    except IOError as msg:
        sys.stderr.write('%s: Can\'t open: %s\n' % (filename, msg))
        sys.exit(1)

    m = md5()
    try:
        while True:
            data = fp.read(8192)
            if not data:
                break
            m.update(data)
    except IOError as msg:
        sys.stderr.write('%s: I/O error: %s\n' % (filename, msg))
        sys.exit(1)
    sys.stdout.write('%s  %s\n' % (m.hexdigest(), filename))

sys.exit(0)