[Patch #476612] Add test suite for PEP247 compliance

Lib/test/test_pep247.py

+#
+# 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')