mock implements a Mocking and Testing Library in Python mock is a Python module that provides a core Mock class. It removes the need to create a host of stubs throughout your test suite. The mock module also provides a patch() decorator that handles patching module and class level attributes within the scope of a test, along with sentinel for creating unique objects. mock is tested on Python versions 2.4-2.7 and Python 3. This is required by tahoe-lafs