#

# Test suite to check compliance with PEP 247, the standard API for

# hashing algorithms.

#

import md5, sha, hmac

def check_hash_module(module, key=None):

    assert hasattr(module, 'digest_size'), "Must have digest_size"

    assert (module.digest_size is None or

            module.digest_size > 0), "digest_size must be None or positive"

    if key is not None:

        obj1 = module.new(key)

        obj2 = module.new(key, "string")

        h1 = module.new(key, "string").digest()

        obj3 = module.new(key) ; obj3.update("string") ; h2 = obj3.digest()

        assert h1 == h2, "Hashes must match"

    else:

        obj1 = module.new()

        obj2 = module.new("string")

        h1 = module.new("string").digest()

        obj3 = module.new() ; obj3.update("string") ; h2 = obj3.digest()

        assert h1 == h2, "Hashes must match"

    assert hasattr(obj1, 'digest_size'), "Objects must have digest_size attr"

    if module.digest_size is not None:

        assert obj1.digest_size == module.digest_size, "digest_size must match"

    assert obj1.digest_size == len(h1), "digest_size must match actual size"

    obj1.update("string")

    obj_copy = obj1.copy()

    assert obj1.digest() == obj_copy.digest(), "Copied objects must match"

    assert obj1.hexdigest() == obj_copy.hexdigest(), \

           "Copied objects must match"

    digest, hexdigest = obj1.digest(), obj1.hexdigest()

    hd2 = ""

    for byte in digest:

        hd2 += "%02x" % ord(byte)

    assert hd2 == hexdigest, "hexdigest doesn't appear correct"

    print 'Module', module.__name__, 'seems to comply with PEP 247'

if __name__ == '__main__':

    check_hash_module(md5)

    check_hash_module(sha)

    check_hash_module(hmac, key='abc')