Extensions Docs Server: Uniform handling of file not found errors

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

 #!/usr/bin/env python
 # Copyright (c) 2012 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 json
 import os
 import unittest
 
+from file_system import FileNotFoundError
 from file_system_cache import FileSystemCache
 from local_file_system import LocalFileSystem
 from api_data_source import APIDataSource
 
 class FakeSamplesDataSource:
   def Create(self, request):
     return {}
 
 class APIDataSourceTest(unittest.TestCase):
   def setUp(self):
     self._base_path = os.path.join('test_data', 'test_json')
 
   def _ReadLocalFile(self, filename):
     with open(os.path.join(self._base_path, filename), 'r') as f:
       return f.read()
 
   def testSimple(self):
     cache_builder = FileSystemCache.Builder(LocalFileSystem(self._base_path))
     data_source_factory = APIDataSource.Factory(cache_builder,
-                                                './',
+                                                '.',
                                                 FakeSamplesDataSource())
     data_source = data_source_factory.Create({})
 
     # Take the dict out of the list.
     expected = json.loads(self._ReadLocalFile('expected_test_file.json'))
     expected['permissions'] = None
     self.assertEqual(expected, data_source['test_file'])
     self.assertEqual(expected, data_source['testFile'])
     self.assertEqual(expected, data_source['testFile.html'])
-    self.assertRaises(OSError, data_source.get, 'junk')
+    self.assertRaises(FileNotFoundError, data_source.get, 'junk')
 
 if __name__ == '__main__':
   unittest.main()