Check in a fair amount of debugging that shows exactly what the issue is. The problem is that Views::DevelopmentModeSystemSpec::Edit is not getting unloaded, causing it to hang on to a copy of Views::Base that's old and no longer bound to the constant Views::Base. So, when we reload this file, we try to make it a subclass of the new, real Views::Base, and it fails. Why this is is still a mystery, but this shows what's going on...