Pex extension for generating user input validation code for web applications

The code written by a software developer is not always flawless. The more code is created the more errors are introduced into the system. In web development different programming languages can be used to implement back-end and front-end sides of the application. For example, it is possible to implement user input validation multiple times —it validates the input values on client-side using JavaScript before the data is sent to server and then the received data is validated again on the server-side. The logic is duplicated, changes made to the validation code must be synchronised on both sides. All implementations must be also unit tested, which increases the time required to create and maintain multiple sets of unit tests. In this paper, we will describe how white-box testing tool Pex can be extended to generate user input validation code for ASP.NET MVC web applications. The validation code won't be duplicated in JavaScript on the client-side and the application will be protected from sending invalid input values from the client-side. The testers can focus on testing using meaningful data input values. Testing of corner cases can be automated thus saving the available resources— testers involved in testing and time spent on testing.