Here are some really simple tests that all GUI developers should be able to perform. It's not an exhaustive analysis by any means, but it will capture some of the most common accessibility failures. It's so simple, even a caveman can do it.

1. Unplug your mouse. Now, use your GUI via the keyboard alone. Can you accomplish what you expect users to accomplish?

2. Go to System->Preferences->Appearance and select the high contrast large print inverse theme. Do the colors, fonts, and font sizes change in your GUI?

3. Run accerciser. Find your application in the left hand panel. Does it appear in the list? Look at the hierarchy via accerciser. Does the hierarchy look complete? It should mirror the GUI hierarchy.

4. Are you creating custom widgets? If so, analyze them using accerciser. You should be able to get textual equivalents for them using AT-SPI and accerciser will be able to show these to you.

5. For extra credit, run orca and tab/arrow around your GUI. Does orca speak at least something when you move between objects? It should at least kind of sound like it's telling you something meaningful about the object you landed on. For bonus points, cover or turn off your monitor. Can you still use your GUI?

This is a very quick set of things YOU THE GUI DEVELOPER can do as a very quick smoke test to evaluate your GUI. You will be able to do it much faster than the accessibility folks can do it because you already know how to build/install your module and all of the sundry of quirks and other dependencies needed to build it.

Please take the time to do this for your GUI and let the accessibility team know how it works out. The team can then work with you to help you understand what is needed and how you can fix the problems.