Docserver: Make MockFileSystem not iterate over the entire file system as part

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 8bcea45966b23c1b781964cbf415028ecbfb6e3a..6831f368367feadbedd3d2ba1c7b4424b9f0d45f 100755
--- a/chrome/common/extensions/docs/server2/caching_file_system_test.py
+++ b/chrome/common/extensions/docs/server2/caching_file_system_test.py
@@ -137,7 +137,7 @@ class CachingFileSystemTest(unittest.TestCase):
         tuple(future.Get() for future in futures))
     self.assertTrue(*mock_fs.CheckAndReset(read_resolve_count=3))
 
-    test_fs.IncrementStat(path='bob/')
+    test_fs.IncrementStat(path='bob/bob0')
     file_system = create_empty_caching_fs()
     self.assertEqual('bob/bob1 contents',
                      file_system.ReadSingle('bob/bob1').Get())