I just wish there was an rspec configuration that forced the `to be_*` and `not_to be_*` tests to force `true` and `false` rather than truthy or falsey values. When I design an API I like to be absolutely precise about what the return values are. I hate it when APIs are loose, and you can get truthy or falsey values in one context, and in another you get an integer or string (like `Kernel#defined?`) that you can interpret a whole other way -- add a second method if you want to extend the behaviour.

I like the test that is here now though, I think it's more precise.