Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, are described that enable automated testing of web applications. Techniques include receiving a web application and a test script including user-specified instructions for testing the web application. The user-specified instructions are converted into commands that include first-type commands executable by a browser automation module to control operations of a web browser, and second-type commands that are not executable by the browser automation module, where the total number of commands exceeds a number of instructions in the test script. The first-type commands are provided for execution to the browser automation module to control operations of the web browser, and the second-type commands are executed to control operations of the at least one computer that cannot be controlled by the browser automation module. A report is output based on executing the first-type and second-type commands.