Refactor how net/data/verify_certificate_chain_unittest/*

net/data/verify_certificate_chain_unittest/violates-pathlen-1-constrained-root/generate-chains.py

 #!/usr/bin/python
 # Copyright (c) 2016 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 with 2 intermediates and one end entity certificate. The
 root certificate has a pathlen:1 restriction, and constraints are enforced
 on this trust anchor making it an invalid chain."""
 
+import sys
+sys.path += ['..']
+
 import common
 
 # Self-signed root certificate (used as trust anchor).
 root = common.create_self_signed_root_certificate('Root')
 root.get_extensions().set_property('basicConstraints',
                                    'critical,CA:true,pathlen:1')
 
 # Intermediate 1 (no pathlen restriction).
 intermediate1 = common.create_intermediate_certificate('Intermediate1', root)
 
 # Intermediate 2 (no pathlen restriction).
 intermediate2 = common.create_intermediate_certificate('Intermediate2',
                                                        intermediate1)
 
 # Target certificate.
 target = common.create_end_entity_certificate('Target', intermediate2)
 
-chain = [target, intermediate2, intermediate1]
-trusted = common.TrustAnchor(root, constrained=True)
-time = common.DEFAULT_TIME
-key_purpose = common.DEFAULT_KEY_PURPOSE
-verify_result = False
-errors = """----- Certificate i=1 (CN=Intermediate2) -----
-ERROR: max_path_length reached
-
-"""
-
-common.write_test_file(__doc__, chain, trusted, time, key_purpose,
-                       verify_result, errors)
+chain = [target, intermediate2, intermediate1, root]
+common.write_chain(__doc__, chain, 'chain.pem')