1. A computer-implemented method of testing interoperability of a web service against a plurality of web services tools, comprising the steps of: providing a web services description language file (WSDL) that describes the web service to be tested; selecting at least one of the plurality of web services tools; generating and compiling sets of proxy files for each selected web service tool based upon the provided WSDL file and loading the generated and compiled proxy files into memory; generating an XML test case for each of the generated and compiled sets of proxy files, the XML test case including dummy variables for each operation of the provided WSDL file; populating the generated XML test case with values for at least some of the dummy variables, and invoking a targeted web service from a selected client platform using the populated XML test case and providing results for each invocation.