Web-services are supported by a complex software infrastructure that must provide a robust service to the client applications. This practical experience report presents a practical approach for the evaluation of the robustness of web-services infrastructures. A set of robustness tests (i.e., invalid web-services call parameters) is applied during web-services execution in order to reveal possible robustness problems in the webservices code and in the application server infrastructure. The approach is illustrated using two different implementations of the web-services specified by the TPC-App performance benchmark running on top of the JBoss application server. The proposed approach is generic and can be used to evaluate the robustness of web-services implementations (relevant for programmers) and application server infrastructures (relevant for administrators and system integrators).