Error at the end of a capybara autotest... every time

With autospec / cucumber / capybara running my feature tests I get this line even after going green:

(eval):1:in 开发者_如何学编程`initialize': can't convert String into Integer (TypeError)

Anyone know what this is? I thought it was me, then heard another dev was seeing it to, and when googling I see it in the screen logs on various issues at the capybara github, but I don't see anyone addressing it.

I'm going to ignore it, assuming its not something that I'm doing, but was just curious about it.

This used to happen with Culerity 0.2.3 but I believe was subsequently resolved.