'Create fake filesystem.'

def setUp(self):

    super(GRRTempFileTestDirectory, self).setUp()
    self.prefix = config.CONFIG.Get('Client.tempfile_prefix')
    self.existsdir = os.path.join(self.temp_dir, 'this/exists/')
    os.makedirs(self.existsdir)
    self.not_exists = os.path.join(self.temp_dir, 'does/not/exist/')
    self.new_temp_file = os.path.join(self.not_exists, self.prefix)
