Following redirection in ControllerTests

It’s just fine pattern wise. It’s not exactly the same, but our context generators make use of redirected_params to construct a path and then get the show page of a created resource:

https://github.com/phoenixframework/phoenix/blob/444569fb99a599d67ec16fd492c3681412dd5759/priv/templates/phx.gen.html/controller_test.exs#L33-L35