omniauth.rb

class TestOmniAuth
  attr_reader :app, :env

  def initialize(app)
    @app = app
  end

  def call(env)
    @env = env
    if request.path =~ /auth\/facebook\/callback/
      omniauth_hash = {
        'uid' => '1234',
        'provider' => 'facebook',
        'user_info' => {
          'id'        => '1234',
          'link'      => 'http://facebook.com/foo',
          'email'     => '[email protected]',
          'first_name'=> 'Foo',
          'last_name' => 'Bar',
          'website'   => 'http://example.com'
        }
      }
      @env['omniauth.auth'] = omniauth_hash
      @app.call(env)
    elsif request.path =~ /auth\/facebook$/
      r = Rack::Response.new("")
      r.redirect "http://www.example.com/auth/facebook/callback"
      r.finish
    else
      @app.call(env)
    end
  end

  def request
    @request ||= Rack::Request.new(@env)
  end

  def full_host
    uri = URI.parse(request.url)
    uri.path = ''
    uri.query = nil
    uri.to_s
  end
end

Around('@stub_facebook') do |scenario, block|
  class OmniAuth::Builder
    alias_method :orig_call, :call
    def call(env)
      TestOmniAuth.new(@app).call(env)
    end
  end

  #for some reason this doesn't work
  Rails.application.config.middleware.swap OmniAuth::Builder, TestOmniAuth
  result = block.call

  class OmniAuth::Builder
    alias_method :call, :orig_call
  end
end