The reason why I use 'calledWith' here because I want to verify the parameter. Some case will need no parameter but some will need 'true' as parameter(please ref https://github.com/steveck-chung/gaia/commit/40f1392f5f1a0f8b0c4e6e10caac58f0983345ac#L6R125). Do you think that we should verify called and args separately?