Chapter 13: Graphical User Interfaces

Overview

Readers who have gotten this far probably noticed that the "special cases" discussed in the second part of this book are nothing more than the same issue in recurring variations: the structure or interface design of a ready-to-use framework, a tool, or an API hampers the testing of the actual functionality.

Graphical user interfaces (GUIs) are no exception in this respect, because their implementation relies on the use of AWT or Swing, as well as additional components (e.g., Java2D). This situation is topped by an important aspect we already saw in connection with Web applications: A "good" user interface not only has to have clearly testable properties, it is also subject to unclear evaluation criteria, such as ergonomics, intuitive use, and esthetics, or in short usability [Nielsen94]. In contrast to what's required by the test-first approach, these criteria cannot be specified in advance. For this reason, it is not surprising that the test-first development of a GUI cannot cover all desirable aspects.

Nevertheless, we as test-first representatives are not left empty-handed in this issue either, as we will see in this chapter.