Weird behaviour involving controllers, modules, namespaces and functional tests

Weird one here.

I was working on some code that had controllers within a namespace (Admin::ThingyController). The controller descended from an Admin::BaseController. And Admin::BaseController included a module (include GenericStuff), which in turn was defined within the Admin namespace.

So far, so good.

The code-base was actually somebody elses and the time came for me to add a new controller into the Admin namespace. So away I went: ruby script/generate controller admin/another_controller, editing the file so that Admin::AnotherController descends from Admin::BaseController.

Then, as I do, I filled out my functional tests, made them pass (ruby test/functional/admin/another_controller_test.rb) and then built up some (reasonably) nice views and examined them in my browser.

All good. The views worked, the tests passed, the controller did what it was supposed to.

One final check before committing to svn - rake. Bugger. A whole load of failures. What have I broken? Eh? It's AnotherController that is failing. Check it in the browser. All good. Check the test individually. Row of dots. Try rake test:functionals. Blam!

To cut a long story short (actually the story is pretty short, it was the investigation that was long) the cause was the included module in the BaseController. What is particularly weird is that it was only AnotherController that had the failures, even though all the controllers within the admin namespace were defined the same way. Adding the new controller had upset the rake loader somehow.

And the fix? Change the include in BaseController from include GenericStuff to include Admin::GenericStuff (even though the admin prefix is not necessary as both GenericStuff and BaseController are within the same namespace). Now they all work - tests, rake and in the browser.