[Predator] Add local cache for get command output.

appengine/findit/common/test/cache_decorator_test.py

 # Copyright 2015 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 os
 import pickle
 import zlib
 
 from google.appengine.api import memcache
 
 from testing_utils import testing
 
 from common import cache_decorator
 
+_LOCAL_CACHE_TEST_DIR = os.path.join(os.path.expanduser('~'), '.test_cache')

[Martin Barbella, 2016/10/26 23:21:20]

Could you use https://pypi.python.org/pypi/pyfakefs here? I really don't like
the idea of having tests actually write to this directory. It can be fairly
painful to maintain, and could be nondeterministic between runs for many, many
reasons (cleanup and all of the usual IO problems).

[Sharu Jiang, 2016/10/27 21:59:05]

The pyfakefs is third_party libs, use mock instead.

+
 
 class _DummyCacher(cache_decorator.Cacher):
   def __init__(self, cached_data):
     self.cached_data = cached_data
 
   def Get(self, key):
     return self.cached_data.get(key)
 
   def Set(self, key, data, expire_time=0):
     self.cached_data[key] = data
@@ skipping 131 matching lines @@
         return self.url + '/' + path
 
     a1 = A('http://test', 3)
     self.assertEqual('http://test/p1', a1.Func('p1'))
     self.assertEqual('http://test/p1', a1.Func('p1'))
     self.assertEqual(1, a1.runs)
 
     a2 = A('http://test', 5)
     self.assertEqual('http://test/p1', a2.Func('p1'))
     self.assertEqual(0, a2.runs)
+
+  def testLocalCacher(self):
+    cacher = cache_decorator.LocalCacher(cache_dir=_LOCAL_CACHE_TEST_DIR)
+    cacher.Set('a', 'b')
+    self.assertEqual('b', cacher.Get('a'))
+    cacher.Set('c', 'd')
+    self.assertEqual('d', cacher.Get('c'))
+    self.assertIsNone(cacher.Get('uncached_key'))