rails/rails — pull request #14783 by hakanensari (2014-04-16 21:54:40+00:00)
Title: Autoload ActiveModel::StrictValidationFailed

Currently, if environment doesn’t eager load the code, invoking this constant before calling `#valid?` on a model instance results in a `NameError`.

I ran into this while testing a model with strict validation with `assert_raise`, which happens to require one to invoke the error constant first. You can also reproduce this by simply invoking the error in console.