This document discusses web services testing using SOAPUI. It defines a web service as an application without a GUI that takes XML input, processes the data, and provides XML output. It describes how XML is used to define the format of data exchanged between systems, and how WSDL defines the format of input and output for a web service as well as the services it exposes. It identifies SOAP and REST as types of web services and discusses how SoapUI is used to generate XML requests, send them to web services, receive and validate the XML responses, and generate reports.