Add scripts to generate simple test data for certificate verification.

net/data/verify_certificate_chain_unittest/generate-target-has-keycertsign-but-not-ca.py

Index: net/data/verify_certificate_chain_unittest/generate-target-has-keycertsign-but-not-ca.py
diff --git a/net/data/verify_certificate_chain_unittest/generate-target-has-keycertsign-but-not-ca.py b/net/data/verify_certificate_chain_unittest/generate-target-has-keycertsign-but-not-ca.py
new file mode 100755
index 0000000000000000000000000000000000000000..fa3cafb4022cb6647b30e53c9024e0dd2eb54db3
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+++ b/net/data/verify_certificate_chain_unittest/generate-target-has-keycertsign-but-not-ca.py
@@ -0,0 +1,30 @@
+#!/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 with 1 intermediary, a trusted root, and a target
+certificate that is not a CA, and yet has the keyCertSign bit set. Verification
+is expected to fail, since keyCertSign should only be asserted when CA is
+true."""
+
+import common
+
+# Self-signed root certificate (part of trust store).
+root = common.create_self_signed_root_certificate('Root')
+
+# Intermediary certificate.
+intermediary = common.create_intermediary_certificate('Intermediary', root)
+
+# Target certificate (end entity but has keyCertSign bit set).
+target = common.create_end_entity_certificate('Target', intermediary)
+target.get_extensions().set_property('keyUsage',
+    'critical,digitalSignature,keyEncipherment,keyCertSign')
+
+
+chain = [target, intermediary]
+trusted = [root]
+time = common.DEFAULT_TIME
+verify_result = False
+
+common.write_test_file(__doc__, chain, trusted, time, verify_result)