This work aims at exploring the software requirements, described in the form of use cases, as an instrument to support the automatic generation and execution of functional tests, in order to automatically check if the results obtained in the tests generated and executed are in accordance with specified. The establishes a process and a tool for documenting use cases and automatically generating and executing test scripts that verify the behavior of web applications. The content of the use case, especially the flow of events (main and alternative), is structured in accordance to a "behavior model" that stores the test data and generates input for a browser testing tool. In this work, we have used the Selenium tool to automate the interaction with the browser. The assessment of our approach involved the application of the process and generating tool in real systems, comparing the results with other techniques applied in the same systems.