Change ChromiumCommit.format_patch to use a filtered list of files

third_party/WebKit/Tools/Scripts/webkitpy/w3c/chromium_commit_unittest.py

 # Copyright 2016 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 unittest
 from webkitpy.common.host_mock import MockHost
 from webkitpy.common.system.executive_mock import MockExecutive2
 from webkitpy.w3c.chromium_commit import ChromiumCommit
+from webkitpy.w3c.test_exporter import CHROMIUM_WPT_DIR
+from webkitpy.w3c.test_exporter_unittest import mock_command_exec
 
 
 class ChromiumCommitTest(unittest.TestCase):
 
     def test_accepts_sha(self):
         chromium_commit = ChromiumCommit(MockHost(), sha='deadbeefcafe')
 
         self.assertEqual(chromium_commit.sha, 'deadbeefcafe')
         self.assertIsNone(chromium_commit.position)
 
     def test_derives_sha_from_position(self):
         host = MockHost()
         host.executive = MockExecutive2(output='deadbeefcafe')
         pos = 'Cr-Commit-Position: refs/heads/master@{#789}'
         chromium_commit = ChromiumCommit(host, position=pos)
 
         self.assertEqual(chromium_commit.position, 'refs/heads/master@{#789}')
         self.assertEqual(chromium_commit.sha, 'deadbeefcafe')
+
+    def test_filtered_changed_files_blacklist(self):
+        host = MockHost()
+
+        fake_files = ['file1', 'MANIFEST.json', 'file3']
+        qualified_fake_files = [CHROMIUM_WPT_DIR + f for f in fake_files]
+
+        host.executive = mock_command_exec({
+            'diff-tree': '\n'.join(qualified_fake_files),
+            'crrev-parse': 'fake rev',
+        })
+
+        position_footer = 'Cr-Commit-Position: refs/heads/master@{#789}'
+        chromium_commit = ChromiumCommit(host, position=position_footer)
+
+        files = chromium_commit.filtered_changed_files()
+
+        expected_files = ['file1', 'file3']
+        qualified_expected_files = [CHROMIUM_WPT_DIR + f for f in expected_files]
+
+        self.assertEqual(files, qualified_expected_files)