The Grid Execution Management for Legacy Code Architecture (GEMLCA) enables the exposure of legacy applications as Grid services without code re-engineering and with minimum user effort. GEMLCA is integrated with the P-GRADE Grid portal that provides a user-friendly Web interface to convert legacy applications into Grid services, and to create, submit and monitor the execution of complex Grid workflows composed of legacy and non-legacy components. However, users cannot be sure that the selected resources where the execution of workflow components is mapped are functioning properly. This paper describes how the current GEMLCA P-GRADE portal architecture is extended with resource testing capabilities allowing users to select only tested GEMLCA and Globus resources prior to workflow execution, or when recovering a failed workflow. It is also outlined, how the architecture can be extended in order to enhance the capabilities of current production Grid systems and Grid brokers with reliable and accurate resource availability information.