sign_in_spec.rb

require 'spec_helper'

feature 'Signing in' do
  before do
    create(:user)
    visit '/signin'
  end

  scenario 'Successful sign in' do
    fill_in "Login", :with => "[email protected]"
    fill_in "Password", :with => "password"
    click_button "Sign in"
    page.should have_content("Signed in successfully.")
  end
end

user_factory.rb

FactoryGirl.define do
  factory :user do
    email "[email protected]"
    username "testuser"
    name "Test User"
    password "password"
    password_confirmation "password"
  end
end