Add scripts to generate simple test data for certificate verification.

net/data/verify_certificate_chain_unittest/generate-intermediary-basic-constraints-ca-false.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.
+
+import os
+import sys
+
+sys.path.insert(0, os.path.dirname(__file__))
+import common
+
+description = """Simple certificate chain with 1 intermediary and a trusted
+root. The intermediary has a basic constraints extension that indicates it is
+NOT a CA"""
+
+common.Init(__file__)
+
+# Self-signed root certificate (part of trust store).
+root = common.CreateSelfSignedRootCertificate('Root')
+
+# Intermediary with incorrect basic constraints.
+intermediary = common.CreateIntermediaryCertificate('Intermediary', root)
+intermediary.GetExtensions().SetProperty('basicConstraints',
+                                         'critical,CA:false')
+
+# Target certificate.
+target = common.CreateEndEntityCertificate('Target', intermediary)
+
+chain = [target, intermediary]
+trusted = [root]
+time = common.DEFAULT_TIME
+verify_result = False
+
+common.WriteTestFile(description, chain, trusted, time, verify_result)