core/test/integration_test/features/step_definitions/login.rb

Given(/^I am on Karmen homepage$/) do
  visit 'http://karmen:3000/login'
end

When(/^I fill the form with username and password$/) do
  fill_in('username', with: 'andrea.fazzi')
  fill_in('password', with: 'test123')
  click_button('Login')
end

Then(/^I should gain access to the application$/) do
  expect(page).to have_content 'Super-secret'
end