An automated oracle for verifying GUI objects

Reviewer: John R. Dance

The author describes a tool that can help verify the correctness of graphical output. A common method of image testing is to do a bit-by-bit comparison. This tool attempts to raise image comparison to a logical level by capturing the graphical application programming interface (API) calls and then doing some comparisons of the results. It appears to be successful in some small test cases. In short, the tool captures graphical API calls and boils them down into the set of points used in the drawing API. Given this set of points, a second image can be compared by looking either at the point set itself, or by looking at the angles and lengths of the vectors to those points. Looking at the angles and lengths allows scaled images to be compared. While this tool appears to work in these two test cases, there are plenty of drawbacks. For example, image rotation, translation, and skewing cannot be tested. In addition, inclusion of bitmap images will cause the comparisons to fall back to a bit-by-bit style. While the paper succeeded in making me think of additional uses or variations of this technique, the English is rather poor and makes the paper hard to follow in places. There are four references; however, a quick search on the Web resulted in many relevant and related topics. Not being an expert in GUI testing techniques, I wonder how much these techniques have been tried and/or documented by others. Online Computing Reviews Service