Hi,
I’ve written a guide to using TestFX, based on my experience working an Open Source JavaFX project. Take a look - I hope you find it useful:
http://vocabhunter.github.io/2016/07/27/TestFX.html
To quote my final paragraph:
Finally, I would like to thank the authors of and contributors to the TestFX project. There are a wealth of great Open Source libraries out there and sometimes it is easy to forget that each such project came about as a result of the time and effort that individuals put into building great software to share with others. Well done and thanks to everyone who helped to make TestFX such a useful framework!
Kind regards, Adam Carroll.