创建的对象在rspec中的控制器操作中不可用？

I'm trying to create a login action within a helper module that will create a new user and log me in as that user. Since I am using capybara with capybara-webkit driver, the post or submit methods are not available, so I can't simply post to the login path with the proper parameters. My current approach then is to actually visit the login path and fill out the login form with the newly created user's username and password. Here's the helper function I'm trying to create (in spec/support/session_macros.rb):I'm trying to create a login action within a he