Refactor how net/data/verify_certificate_chain_unittest/*

net/data/verify_certificate_chain_unittest/target-wrong-signature/generate-chains.py

 #!/usr/bin/python
 # Copyright (c) 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Certificate chain where the target has an incorrect signature. Everything
 else should check out, however the digital signature contained in the target
 certificate is wrong."""
 
+import sys
+sys.path += ['..']
+
 import common
 
 # Self-signed root certificate (used as trust anchor).
 root = common.create_self_signed_root_certificate('Root')
 
 # Intermediate certificate to include in the certificate chain.
 intermediate = common.create_intermediate_certificate('Intermediate', root)
 
 # Actual intermediate that was used to sign the target certificate. It has the
 # same subject as expected, but a different RSA key from the certificate
 # included in the actual chain.
 wrong_intermediate = common.create_intermediate_certificate('Intermediate',
                                                             root)
 
 # Target certificate, signed using |wrong_intermediate| NOT |intermediate|.
 target = common.create_end_entity_certificate('Target', wrong_intermediate)
 
-chain = [target, intermediate]
-trusted = common.TrustAnchor(root, constrained=False)
-time = common.DEFAULT_TIME
-key_purpose = common.DEFAULT_KEY_PURPOSE
-verify_result = False
-errors = """----- Certificate i=0 (CN=Target) -----
-ERROR: Signature verification failed
-ERROR: VerifySignedData failed
-
-"""
-
-common.write_test_file(__doc__, chain, trusted, time, key_purpose,
-                       verify_result, errors)
+chain = [target, intermediate, root]
+common.write_chain(__doc__, chain, 'chain.pem')