Add scripts to generate simple test data for certificate verification.

net/data/verify_certificate_chain_unittest/generate-basic-constraints-pathlen-0-self-issued.py

Index: net/data/verify_certificate_chain_unittest/generate-basic-constraints-pathlen-0-self-issued.py
diff --git a/net/data/verify_certificate_chain_unittest/generate-basic-constraints-pathlen-0-self-issued.py b/net/data/verify_certificate_chain_unittest/generate-basic-constraints-pathlen-0-self-issued.py
new file mode 100755
index 0000000000000000000000000000000000000000..80c0fc48f339d1ee8973ed2088c1ba383c33ee56
--- /dev/null
+++ b/net/data/verify_certificate_chain_unittest/generate-basic-constraints-pathlen-0-self-issued.py
@@ -0,0 +1,35 @@
+#!/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 2 intermediaries. The first intermediary has a basic
+constraints path length of 0. The second one is self-issued so does not count
+against the path length."""
+
+import common
+
+# Self-signed root certificate (part of trust store).
+root = common.CreateSelfSignedRootCertificate('Root')
+
+# Intermediary with pathlen 0
+intermediary1 = common.CreateIntermediaryCertificate('Intermediary', root)
+intermediary1.GetExtensions().SetProperty('basicConstraints',
+                                          'critical,CA:true,pathlen:0')
+
+# Another intermediary (with the same pathlen restriction).
+# Note that this is self-issued but NOT self-signed.
+intermediary2 = common.CreateIntermediaryCertificate('Intermediary',
+                                                     intermediary1)
+intermediary2.GetExtensions().SetProperty('basicConstraints',
+                                          'critical,CA:true,pathlen:0')
+
+# Target certificate.
+target = common.CreateEndEntityCertificate('Target', intermediary2)
+
+chain = [target, intermediary2, intermediary1]
+trusted = [root]
+time = common.DEFAULT_TIME
+verify_result = True
+
+common.WriteTestFile(__doc__, chain, trusted, time, verify_result)