I’ve been working on a greybox testing strategy for my company, Cantina for a while now, and I’ve written the first versions of the libraries to support it, one for the JUnit backend, and one for the Nightwatch frontend. You can find them here:
I’ll be publishing some articles about how I arrived at this strategy and how to use it in the near future. Unit then, you can check out the in-progress field guide, which contains an overview of my development process which covers testing.
UPDATE: I’m leaving Cantina on January 17th, 2017. They have graciously offered to assign copyright to me for the libraries and I have purchased the domain, graybox-testing.org to host resources around this style of testing. I’ve updated the links above to point to my personal repo.