testing.md

Testing

Lazy compilation

Webpacker lazily compiles assets in test env so you can write your tests without any extra setup and everything will just work out of the box.

Here is a sample system test case with hello_react example component:

// Example react component

import React from 'react'
import ReactDOM from 'react-dom'
import PropTypes from 'prop-types'

const Hello = props => (
  <div>Hello David</div>
)

document.addEventListener('DOMContentLoaded', () => {
  ReactDOM.render(
    <Hello />,
    document.body.appendChild(document.createElement('div')),
  )
})

<%# views/pages/home.html.erb %>

<%= javascript_pack_tag "hello_react" %>

# Tests example react component
require "application_system_test_case"
class HomesTest < ApplicationSystemTestCase
  test "can see the hello message" do
    visit root_url
    assert_selector "h5", text: "Hello! David"
  end
end