Abstract: The present invention is a module testing tool for Web services. In one embodiment, the present invention automates the testing of Web services that use SOAP as a wire protocol and HTTP as a transport protocol. The invention provides an easy interface for exercising Web services and testing their functionality. The invention helps users confirm the responses to SOAP messages with such features as fault detection, textual comparisons, XML validation by DTDs or XML Schemas, and the ability to express and flag complex patterns in XML. The invention lets the users validate responses that require application-specific verification (such as business logic validation) by plugging in their own code. It also provides the capability to perform regression testing of web services. The invention can automatically creates regression test controls from SOAP Client responses, or users can create their own regression tests.