Hi! I've got a question about ActionController::TestCase#post in Rails 5.1
http://api.rubyonrails.org/v5.1/classes/ActionController/TestCase.html - The documentation suggests that calling #post with a document as a second argument should still be possible, e.g. `post :create, json`
I might be misreading, but https://github.com/rails/rails/commit/98b8309569a326910a723f521911e54994b112fb (introduced in Rails 5.1) makes it look like that no longer works?