We've used it in at least one internal project. I found it to lessen readability and make maintenance harder. It could be the way things were set up. I like the

We've used it in at least one internal project. I found it to lessen readability and make maintenance harder. It could be the way things were set up. I like the basic idea, but that lib just wasn't doing it for me. We got close to something usable with test case generators where you replaced the intended bad value(s). There ended up being too much indirection for my taste for too little reward.