Ruby Yagi - Introduction to Rails testing with RSpec and Capybara - With Test Helpers

01_bookmark_create_spec.rb

require 'rails_helper'

RSpec.describe 'create bookmark', type: :system, test_helpers: [:bookmarks] do
  before { visit bookmarks_path }

  scenario 'empty title and url' do
    bookmarks.add(title: '', url: '')
    bookmarks.should.have_error("Title can't be blank")
    bookmarks.should_not.have_bookmark('Ruby Yagi')
  end
  
  scenario 'valid title and url' do
    bookmarks.add(url: 'https://rubyyagi.com', title: 'Ruby Yagi')
    bookmarks.should.have_bookmark('Ruby Yagi')
  end
end

02_bookmark_edit_spec.rb

require 'rails_helper'

RSpec.describe 'update bookmark', type: :system, test_helpers: [:bookmarks] do
  let!(:bookmark) { Bookmark.create(url: 'https://rubyyagi.com', title: 'Ruby Yagi') }

  before { visit bookmarks_path }

  scenario 'empty title and url' do
    bookmarks.edit('Ruby Yagi', with: { title: '', url: '' })
    bookmarks.should.have_error("Title can't be blank")

    # The bookmark title should be unchanged
    expect(bookmark.reload.title).to eq('Ruby Yagi')
  end

  scenario 'valid title and url' do
    bookmarks.edit('Ruby Yagi', with: { title: 'Fluffy', url: 'https://fluffy.es' })

    bookmarks.should_no_longer.have_bookmark('Ruby Yagi')
    bookmarks.should_now.have_bookmark('Fluffy')
  end
end

03_bookmark_delete_spec.rb

require 'rails_helper'

RSpec.describe 'delete bookmark', type: :system, test_helpers: [:bookmarks] do
  let!(:bookmark) { Bookmark.create(url: 'https://rubyyagi.com', title: 'Ruby Yagi') }

  before { visit bookmarks_path }

  scenario 'removing an existing bookmark' do
    bookmarks.delete('Ruby Yagi')
    bookmarks.should_no_longer.have_bookmark('Ruby Yagi')

    expect(Bookmark.count).to eq 0
  end
end

04_bookmarks_test_helper.rb

class BookmarksTestHelper < Capybara::TestHelper
  aliases(
    error_summary: '#error_explanation',
    save_button: [:button, type: 'submit'],
  )

  def bookmark_by_title(title)
    find(:table_row, { 'Title' => title })
  end

  def add(attrs)
    click_link('New Bookmark')
    save_bookmark(attrs)
  end

  def edit(title, with:)
    bookmark_by_title(title).click_link('Edit')
    save_bookmark(with)
  end

  def delete(title)
    accept_confirm { bookmark_by_title(title).click_link('Destroy') }
  end

  def save_bookmark(attrs)
    fill_in 'Title', with: attrs[:title]
    fill_in 'Url', with: attrs[:url]
    save_button.click
  end

  def have_bookmark(title)
    have(:table_row, { 'Title' => title })
  end

  def have_error(message)
    have(:error_summary, message)
  end
end

05_readme.md

Notice how we make the test more robust by checking that the bookmarks are being displayed in the index page with the proper title.

Also, we don't click Edit or Destroy anywhere in the page, we instead restrict these actions to be inside the bookmark we expect to find in the page.

This subtle difference is very important to prevent flaky tests and false positives.

A more complete example could abstract the common functionality into a TableTestHelper or FormTestHelper, reducing the amount of duplication when we test similar CRUDs.