'Should return None when the PID file does not exist.'

def test_returns_none_when_file_nonexist(self):

    set_pidlockfile_scenario(self, 'not-exist')
    pidfile_path = self.scenario['path']
    pid = pidlockfile.read_pid_from_pidfile(pidfile_path)
    scaffold.mock_restore()
    self.failUnlessIs(None, pid)
