EXDIFF is a test evaluation facility that extends commonly available file comparison utilities. It works as a stand-alone or within TestWorks' fully integrated STW/Regression tool set. File comparison includes ASCII and binary files, and bitmap image files saved either with SR's Capture/Playback tool, CAPBAK or the standard X Window Dump utility (xwd).

EXDIFF provides masking options which allow the user to specify areas within ASCII or image files to be ignored during the differencing process. While masking is concerned with positive masks (i.e. ignoring regions within specified boundaries), the EXDIFF inverse mask option enables negative masks to be differenced. In this mode, EXDIFF compares only the areas contained within the masked boundaries.

Xexdiff, the X Window system version of EXDIFF, performs a pixel-by-pixel comparison of the two saved image files and displays compared or differenced images to the screen. It indicates differences between image file colors; and it provides line and byte comparisons with the exdiff utility. Positive or negative mask coordinates are established in the image file using the Xmask utility.

The EXDIFF default mode exdiff differences two ASCII files as line-oriented or byte-oriented files. Results are reported in an easy-to-read format, which indicates the necessary standard line-editor commands to remove existing differences in the compared files. In this mode, EXDIFF is fully compatible with the standard UNIX diff utility. Using the EX utilities, similar ASCII files are reformatted for more reliable differencing with the exdiff utility.

With the help of its other STW/Regression companion tools CAPBAK and SMARTS(tm), the testing process is completely automated. The SMARTS test management system organizes test sessions recorded with CAPBAK into a hierarchical structure for execution individually or as part of a test suite according to the verification method selected. Typically, comparison image files represent baseline output versus newly generated outputs. Discrepancies are reported and stored by SMARTS for further analysis. Extraneous differences can be discarded in the comparison process via the EXDIFF tool. SMARTS automatically generates a variety of reports based on test results.

EXDIFF's masking capabilities are extensive: it can ignore user-specified areas of an image file during the differencing process with the Xexdiff utility; it allows unlimited, overlapping positive masks to be set for an individual image; it enables inverse processing of an image file mask, where only the user-specified area is compared during the differencing process; mask co-ordinates can be established either through the Graphical User Interface (GUI) or set in a configuration file to be read by EXDIFF at the start of execution.

EXDIFF allows trailing blanks (spaces and tabs) to be ignored and strings of blanks to be compared as equal; it reformats and/or divides ASCII files based on user-specified characters strings and text lines, preparing the files for more comprehensive differencing with the exdiff utility.