In this case the tool is meant to parse programming languages, so once I write some parser grammars every valid code file in existence is a test case. Seen that way I have more test cases than I know what to do with.

We've come a ways from 2 + 2. This week my goal is to feed our own whole codebase through the JS parser, and I should be able to. I managed to parse a few hundred lines of real JS last week before running into Automatic Semicolon Insertion trouble that I needed to tinker with the core to fix.

While I get that our low profile smacks of vapor, we actually have working packages published: bablr and @bablr/cli. I'd consider them to be beta quality right now, having gone through many previous releases that I'd only consider alpha-quality, and even more releases before that.