Among the avalanche of code I just open sourced is a humble little application called FeatureProof. This application is an environment for testing features in OpenType fonts.
I’ve been thinking about this tool since TypoTechnica 2005. During a round table discussion at that conference, Erik van Blokland and I made the case for a robust tool for testing OpenType features. Specifically, we stated that we felt that there was a huge need for a tool capable of programmatically testing OpenType features. We had been doing this with our other programming work, so it seemed natural that we should be able to do it with our OpenType feature work.
I waited for someone to build such a tool. Nothing happened, so I decided to build it myself. FeatureProof is the result. It allows you to interactively test features and analyze the results, browse the compiled feature data and execute programmatic test cases. It has become indispensable in my work.
You can download the application over at code.typesupply.com. There is a good bit of documentation there as well.
This is a beta release, so I would appreciate any bug reports.