Benchmark file A file containing the expected result screen images for a test execution. Mask A specified area of a screen image to be ignored or excluded when Result and Benchmark images are compared. Mask file A file used to hide (mask) specified areas of a screen image during a comparison between a Result and Benchmark file. Masking A method used to specify areas in a benchmark file that are to be hidden during test analysis. Result file A file containing the result screen images from a test execution. X Testing Testing of software applications employing an X Windows interface.