<p>The calculations in my code are well-tested, but because there is so much GUI code, my overall code coverage is lower than I'd like. Are there any guidelines on unit-testing GUI code? Does it even make sense?</p>

<p>For example, there are graphs in my app. I haven't been able to figure out how to automate the testing of the graphs. It takes a human eye, AFAIK, to check if the graph is correct.</p>

<p>(I'm using Java Swing)</p>

Designs like MVP and MVC typically try to abstract as much logic out of the actual GUI as possible. One very popular article about this is
"The Humble Dialog Box"
by Michael Feathers. Personally I've had mixed experiences with trying to move logic out of the UI - sometimes it's worked very well, and at other times it's been more trouble than it's worth. It's somewhat outside my area of expertise though.