Graphical user interface testing

In software engineering, graphical user interface testing is the process of testing a product's graphical user interface (GUI) to ensure it meets its specifications. This is normally done through the use of a variety of test cases.

Another method of generating GUI test cases simulates a novice user. An expert user of a system tends to follow a direct and predictable path through a GUI, whereas a novice user would follow a more random path. A novice user is then likely to explore more possible states of the GUI than an expert.

The difficulty lies in generating test suites that simulate 'novice' system usage. Using genetic algorithms have been proposed to solve this problem. Novice paths through the system are not random paths. First, a novice user will learn over time and generally would not make the same mistakes repeatedly, and, secondly, a novice user is following a plan and probably has some domain or system knowledge.

Genetic algorithms work as follows: a set of 'genes' are created randomly and then are subjected to some task. The genes that complete the task best are kept and the ones that do not are discarded. The process is again repeated with the surviving genes being replicated and the rest of the set filled in with more random genes. Eventually one gene (or a small set of genes if there is some threshold set) will be the only gene in the set and is naturally the best fit for the given problem.

In the case of GUI testing, the method works as follows. Each gene is essentially a list of random integer values of some fixed length. Each of these genes represents a path through the GUI. For example, for a given tree of widgets, the first value in the gene (each value is called an allele) would select the widget to operate on, the following alleles would then fill in input to the widget depending on the number of possible inputs to the widget (for example a pull down list box would have one input...the selected list value). The success of the genes are scored by a criterion that rewards the best 'novice' behavior.