assert_template only works when explicitly calling render

[JeanMertz]

Whenever I assert the rendering of a template, I need to explicitly call render inside the call method for the specs to pass.

Going down the stack a bit, it seems that the code breaks at test_helper.rb#L126, more specifically, controller._render_options returns nil without an explicit render.

I searched to see if this was expected test/spec behavior, but I couldn't find others having the same problem, so I suspect it to be related to FocusedController.