login.feature

Given Paul is a registered user
When I log in as Paul
Then I will see Paul's homepage

loginpage.rb

def navigate
   visit 'server/blah'
end

def login_as (username, password)
  fill_in (:username, username)
  fill_in (:password, password)
end

steps.rb

def given_x_is_a_registered_user(username) 
    FactoryGirl.create(:user name => paul)
end

def when_i_log_in_as_x (username)
    loginpage.navigate
    loginpage.login_as(username, defaultpassword)
end

def then_i_will_see_x_homepage(username)
    homepage.is_visible
    homepage.shows_welcome(username)
end