Since 3fd7b31a2aa79dabcc34625c10877fcf737d5855 some tests
were failing with this error:
> Error: Unhandled request in test environment: /c/feature/find_by_slug.json
> (GET) at http://localhost:7357/assets/test-helpers.js
This commit fixes the issue by adding the missing pretender. Also
noticed while fixing this that the parameter for the translation
was incorrect -- it was `group` instead of `groupNames`, so that
is fixed here too, along with moving the onShow functions into
@afterRender decorated private functions. There is no need for the
appevent listeners.