Once WDSL is created using web services, tests cases are written to test for the required standards present in WSDL like which style it is? Does it covers all the required input parameters? What are the datatype for those input parameters? etc.,
Operations provided by the Web Service: Test cases covering the required operations which are present in the web Service for which it was developed.
XML Request message format that sent as SOAP request message: Test cases covering the input data, data type, boundary condition validations, stack overflow validations, functional test cases etc.
XML Response message format received as SOAP response message: Test cases covering the output data and its type, output data validations, stack overflow validations, security test, functional test cases, etc.
A simple local tool or test program that could send XML message request and receive request as XML message response: This refers to the fact that in order to test the WebService, we need to develop a client program through which we can send input data as request and test on the output data received as response.