Using Devise in rspec feature tests

I've written the following rspec feature test spec:

require "rails_helper"

RSpec.describe "Team management", type: :feature do
  user_sign_in

  describe "User creates a new team" do
    ...    
    expect(page).to have_link("#{team_name}")
  end
end

The user_sign_in method is defined in my rails_helper.rb:

ENV['RAILS_ENV'] ||= 'test'
require 'spec_helper'
require File.expand_path('../../config/environment', __FILE__)
require 'rspec/rails'
require 'capybara/rails'

...

module UserSignInHelpers
  def user_sign_in
    before(:each) do
      @request.env['devise.mapping'] = Devise.mappings[:user]

      @current_user = FactoryGirl.create(:user)
      @current_user.confirm

      sign_in :user, @current_user
    end
  end
end

RSpec.configure do |config|
  ...
  # The different available types are documented in the features, such as in
  # http://ift.tt/1hsospt
  config.infer_spec_type_from_file_location!

  config.extend UserSignInHelpers,    type: :controller
  config.extend UserSignInHelpers,    type: :feature
  config.include Devise::TestHelpers, type: :controller
  config.include Devise::TestHelpers, type: :feature
end

The user_sign_in method works from all of my controller specs but when I run my feature spec it fails with:

Team management
  User creates a new team
    example at ./spec/features/user_creates_a_new_team_spec.rb:19 (FAILED - 1)

Failures:

  1) Team management User creates a new team
     Failure/Error: Unable to find matching line from backtrace
     NoMethodError:
       undefined method `env' for nil:NilClass
     # /Users/xxxx/.rvm/gems/ruby-2.2.1/gems/devise-3.5.1/lib/devise/test_helpers.rb:24:in `setup_controller_for_warden'

I don't understand why this works in controller tests and not feature tests. Is there something I can do make this work in feature tests?