Automatic re-execution of the test script.
Test execution tools exist for graphical user interface, GUI, and for character-based interfaces. For GUI applications the tools are able to simulate the movement of mouse and click over buttons & are able to recognize the GUI objects like windows, buttons, fields & various different controls.
When a script has been captured once, it may be executed at any given time again. If the software under testing reacts differently from what was expected at the inserted checkpoints, the execution will report a failure. It is usually also possible to log information during execution.
Test scripts are captured in a specific scripting language. In newer versions of these tools it has become possible to get access to the scripts that have been captured. These are often in a C or Visual Basic like code, and this offers the possibility for editing the scripts, so that, for example, forgotten operations, further control points, or changed values, may be added.
Experience shows that if the scripts are written from scratch, rather than captured, and good and systematic development principles are used, the scripts will be more maintainable. More and more of these tools are therefore used as test execution tools of coded scripts, rather than capture/playback.