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

   1 # Copyright 2013 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 class MockFunction(object):
   6   '''Decorates a function to record the number of times it's called, and
   7   use that to make test assertions.
   8
   9   Use like:
  10
  11   @MockFunction
  12   def my_function(): pass
  13   my_function()
  14   my_function()
  15   self.assertTrue(*my_function.CheckAndReset(2))
  16
  17   or
  18
  19   my_constructor = MockFunction(HTMLParser)
  20   my_constructor()
  21   self.assertTrue(*my_constructor.CheckAndReset(1))
  22
  23   and so on.
  24   '''
  25
  26   def __init__(self, fn):
  27     self._fn = fn
  28     self._call_count = 0
  29
  30   def __call__(self, *args, **optargs):
  31     self._call_count += 1
  32     return self._fn(*args, **optargs)
  33
  34   def CheckAndReset(self, expected_call_count):
  35     actual_call_count = self._call_count
  36     self._call_count = 0
  37     if expected_call_count == actual_call_count:
  38       return True, ''
  39     return (False, '%s: expected %s call(s), got %s' %
  40                    (self._fn.__name__, expected_call_count, actual_call_count))