Теория: Системные тесты

# Запуск системных тестов
bin/rails test:system

# book_test.rb
frozen_string_literal: true

test/system/books_test.rb

require 'application_system_test_case'

class BooksTest < ApplicationSystemTestCase
  setup do
    @book = books(:one)
  end

  test 'visiting the index' do
    visit books_url
    assert_selector 'h1', text: 'Books'
  end

  test 'creating a Book' do
    visit books_url
    click_on 'New Book'

    click_on 'Create Book'

    assert_text 'Book was successfully created'
  end

  test 'updating a Book' do
    visit books_url
    click_on 'Edit', match: :first

    click_on 'Update Book'

    assert_text 'Book was successfully updated'
  end

  test 'destroying a Book' do
    visit books_url
    page.accept_confirm do
      click_on 'Destroy', match: :first
    end

    assert_text 'Book was successfully destroyed'
  end
end