Add scripts to generate simple test data for certificate verification.

net/data/verify_certificate_chain_unittest/generate-intermediary-basic-constraints-not-critical.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 with 1 intermediary and a trusted root. The intermediary
+has a basic constraints extension but does not mark it as critical.
+Verification is expected to succeed, since although not critical, the
+basicConstraints indicates CA=true as expected."""
+
+import common
+
+# Self-signed root certificate (part of trust store).
+root = common.CreateSelfSignedRootCertificate('Root')
+
+# Intermediary with non-critical basic constarints.
+intermediary = common.CreateIntermediaryCertificate('Intermediary', root)
+intermediary.GetExtensions().SetProperty('basicConstraints', 'CA:true')
+
+# Target certificate.
+target = common.CreateEndEntityCertificate('Target', intermediary)
+
+chain = [target, intermediary]
+trusted = [root]
+time = common.DEFAULT_TIME
+verify_result = True
+
+common.WriteTestFile(__doc__, chain, trusted, time, verify_result)