Embodiments are directed towards testing a responsiveness of a graphical user interface (GUI) for an application executing on a computer. During execution of each portion of a test, stimuli may be provided to the application. The stimuli may be provided to the application thread that is associated with rendering graphics for the GUI. Responses from the application to the stimuli may be monitored to determine a responsiveness of the application for at least one portion of the test. The responsiveness may be determined based on a wait time between providing a request and receiving a reply to the request, which may indicate that the application is in a state to accept input through the GUI. Responsiveness may be determined separately for each portion of the test. A displayable report may be generated to include the responsiveness of the application for each portion of the test.