cpython/Lib/test/support/hashlib_helper.py

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import functools
import hashlib
import unittest
try:
import _hashlib
except ImportError:
_hashlib = None
def requires_hashdigest(digestname, openssl=None, usedforsecurity=True):
"""Decorator raising SkipTest if a hashing algorithm is not available
The hashing algorithm could be missing or blocked by a strict crypto
policy.
If 'openssl' is True, then the decorator checks that OpenSSL provides
the algorithm. Otherwise the check falls back to built-in
implementations. The usedforsecurity flag is passed to the constructor.
ValueError: [digital envelope routines: EVP_DigestInit_ex] disabled for FIPS
ValueError: unsupported hash type md4
"""
def decorator(func):
@functools.wraps(func)
def wrapper(*args, **kwargs):
try:
if openssl and _hashlib is not None:
_hashlib.new(digestname, usedforsecurity=usedforsecurity)
else:
hashlib.new(digestname, usedforsecurity=usedforsecurity)
except ValueError:
raise unittest.SkipTest(
f"hash digest '{digestname}' is not available."
)
return func(*args, **kwargs)
return wrapper
return decorator