Capybara

Configuration

Capybara.register_driver :selenium_chrome do |app|
  options = Selenium::WebDriver::Chrome::Options.new
  options.add_argument("--headless=new")
  Capybara::Selenium::Driver.new(app, browser: :chrome, options: options)
end

Capybara.javascript_driver = :selenium_chrome

Example: debugging step definitions

# Saves a screenshot to tmp/capybara
Then "screenshot" do
  @i ||= 0
  @i += 1
  page.save_screenshot("screenshot#{@i}.png", full: true)
  puts "Page screenshot saved to screenshot#{@i}.png"
end

Then "show JavaScript console" do
  puts page.driver.browser.logs.get(:browser)
end

# rubocop:disable Lint/Debugger
Then "pry" do
  binding.pry
end
# rubocop:enable Lint/Debugger

This is some debugging code used to debug test code. I'm not a big believer in test code test code (code being used to test test code). The ||= is a null-coalescing assignment that assigns the instance variable here @i to 0 if @i is nil. It saves screenshots to anki_books/tmp/capybara.

As an experiment to demonstrate the dependency on these debugging steps to Selenium WebDriver, I added Then screenshot to a feature test that had the @javascript tag, removed that tag, and executed the test:

$ bundle exec cucumber features/tests/books/dragging_basic_notes_between_articles.feature
Using the default profile...
# Anki Books, a note-taking app to organize knowledge,
# is licensed under the GNU Affero General Public License, version 3
# Copyright (C) 2023 Kyle Rego
Feature: Creating an article

  Background: Adding an article to a book                                                    # features/tests/books/dragging_basic_notes_between_articles.feature:7
    Given there is a user "test_user", email "test@example.com", and password "1234asdf!!!!" # features/step_definitions/user_steps.rb:16
    And the user "test_user" has a book called "My first book"                               # features/step_definitions/books_steps.rb:7
    Then screenshot                                                                          # features/step_definitions/debugging_steps.rb:8
      Capybara::Driver::Base#save_screenshot (Capybara::NotSupportedByDriverError)
      <internal:kernel>:90:in `tap'
      ./features/step_definitions/debugging_steps.rb:11:in `"screenshot"'
      features/tests/books/dragging_basic_notes_between_articles.feature:10:in `screenshot'
    And the book "My first book" has the article "test article 1"                            # features/step_definitions/article_steps.rb:10
    And the article "test article 1" has 2 basic notes                                       # features/step_definitions/article_steps.rb:15
    And the book "My first book" has the article "test article 2"                            # features/step_definitions/article_steps.rb:10
    And the article "test article 2" has 2 basic notes                                       # features/step_definitions/article_steps.rb:15
    And I am logged in as the user "test_user" with password: "1234asdf!!!!"                 # features/step_definitions/user_steps.rb:7
    And I click the "Books" link                                                             # features/step_definitions/shared/link_steps.rb:7
    And I click the last "My first book" link                                                # features/step_definitions/shared/link_steps.rb:12
    And I click the "My first book" link                                                     # features/step_definitions/shared/link_steps.rb:7

Aside on Ruby constants

# (... means I omitted code)
module Capybara
  ...
  class NotSupportedByDriverError < CapybaraError; end
  ...
end

Example: a step definition that uses a regular expression

When(/^I visit the (?:root|home) page$/) do
  visit('/')
end