Historically, we've tended to put each new class into its own file like this.  However, given ruby 1.9's well-known perf problems with `require`, I've started to put small classes like this in the same file as other related code, which will hopefully keep rspec's boot time down in a reasonable range.

That said, this my be premature optimization (and thus, the root of all evil) and we should probably actually benchmark it rather than just going off my hunch before we make any changes based on this...but I am curious what your thoughts are on the manner.  Would be interesting to compile all of one of rspec's gems into a single file, and see how much a difference that makes in the load time.  And even if it is noticeable, having one giant file sounds awful for maintenance, and there's obviously a balance to be had here...and I'm not yet sure where that is.

(TL;DR: don't move this into another file yet; I'm just musing and am curious on your thoughts).