[tools] add script to simplify backporting patch to Node.js

tools/release/test_backport_node.py

+#!/usr/bin/env python
+# Copyright 2017 the V8 project 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 shutil
+import subprocess
+import sys
+import tempfile
+import unittest
+
+import backport_node
+
+# Base paths.
+BASE_DIR = os.path.dirname(os.path.abspath(__file__))
+TEST_DATA = os.path.join(BASE_DIR, 'testdata')
+
+def gitify(path):
+  files = os.listdir(path)
+  subprocess.check_call(['git', 'init'], cwd=path)
+  subprocess.check_call(['git', 'add'] + files, cwd=path)
+  subprocess.check_call(['git', 'commit', '-m', 'Initial'], cwd=path)
+
+class TestUpdateNode(unittest.TestCase):
+  def setUp(self):
+    self.workdir = tempfile.mkdtemp(prefix='tmp_test_node_')
+
+  def tearDown(self):
+    shutil.rmtree(self.workdir)
+
+  def testUpdate(self):
+    v8_cwd = os.path.join(self.workdir, 'v8')
+    node_cwd = os.path.join(self.workdir, 'node')
+
+    # Set up V8 test fixture.
+    shutil.copytree(src=os.path.join(TEST_DATA, 'v8'), dst=v8_cwd)
+    gitify(v8_cwd)
+
+    # Set up node test fixture.
+    shutil.copytree(src=os.path.join(TEST_DATA, 'node'), dst=node_cwd)
+    gitify(os.path.join(node_cwd))
+
+    # Add a patch.
+    with open(os.path.join(v8_cwd, 'v8_foo'), 'w') as f:
+      f.write('zonk')
+    subprocess.check_call(['git', 'add', 'v8_foo'], cwd=v8_cwd)
+    subprocess.check_call(['git', 'commit', '-m', "Title\n\nBody"], cwd=v8_cwd)
+    commit = subprocess.check_output(['git', 'rev-parse', 'HEAD'], cwd=v8_cwd).strip()
+
+    # Run update script.

[Michael Achenbach, 2017/04/25 12:33:45]

nit: Run backport script.

+    backport_node.Main([v8_cwd, node_cwd, commit, "--no-review"])
+
+    # Check message.
+    message = subprocess.check_output(['git', 'log', '-1', '--format=%B'], cwd=node_cwd)
+    self.assertIn('Original commit message:\n\n    Title\n\n    Body', message)
+
+    # Check patch.
+    gitlog = subprocess.check_output(
+        ['git', 'diff', 'master', '--cached', '--', 'deps/v8/v8_foo'],
+        cwd=node_cwd,
+    )
+    self.assertIn('+zonk', gitlog.strip())
+
+if __name__ == "__main__":
+  unittest.main()