Docserver: Override Walk in CachingFileSystem

chrome/common/extensions/docs/server2/caching_file_system_test.py

Index: chrome/common/extensions/docs/server2/caching_file_system_test.py
diff --git a/chrome/common/extensions/docs/server2/caching_file_system_test.py b/chrome/common/extensions/docs/server2/caching_file_system_test.py
index 78becf1a8dc9c8e35f567662cdae3b73dc266bda..bc12ffb2959bb7ddfc0a30e0efabd9fe22accd28 100755
--- a/chrome/common/extensions/docs/server2/caching_file_system_test.py
+++ b/chrome/common/extensions/docs/server2/caching_file_system_test.py
@@ -251,6 +251,44 @@ class CachingFileSystemTest(unittest.TestCase):
       'bob/bob0': 'bob/bob0 contents',
     }, read_skip_not_found(('bob/bob0', 'bob/bob2')))
 
+  def testWalkCaching(self):
+    test_fs = TestFileSystem({
+      'root': {
+        'file1': 'file1',
+        'file2': 'file2',
+        'dir1': {
+          'dir1_file1': 'dir1_file1',
+          'dir2': {},
+          'dir3': {
+            'dir3_file1': 'dir3_file1',
+            'dir3_file2': 'dir3_file2'
+          }
+        }
+      }
+    })
+    mock_fs = MockFileSystem(test_fs)
+    file_system = self._CreateCachingFileSystem(mock_fs, start_empty=True)
+    for walkinfo in file_system.Walk(''):
+      pass
+    self.assertTrue(*mock_fs.CheckAndReset(
+        read_resolve_count=5, read_count=5, stat_count=5))
+
+    all_dirs, all_files = [], []
+    for root, dirs, files in file_system.Walk(''):
+      all_dirs.extend(dirs)
+      all_files.extend(files)
+    self.assertEqual(sorted(['root/', 'dir1/', 'dir2/', 'dir3/']),
+                     sorted(all_dirs))
+    self.assertEqual(
+        sorted(['file1', 'file2', 'dir1_file1', 'dir3_file1', 'dir3_file2']),
+        sorted(all_files))
+    # All data should be cached.
+    self.assertTrue(*mock_fs.CheckAndReset())
+
+    # Starting from a different root should still pull cached data.
+    for walkinfo in file_system.Walk('root/dir1/'):
+      pass
+    self.assertTrue(*mock_fs.CheckAndReset())
 
 if __name__ == '__main__':
   unittest.main()