Move and rename system tests

* Move system tests back into Action Pack
* Rename `ActionSystemTest` to `ActionDispatch::SystemTestCase`
* Remove private base module and only make file for public
`SystemTestCase` class, name private module `SystemTesting`
* Rename `ActionSystemTestCase` to `ApplicationSystemTestCase`
* Update corresponding documentation and guides
* Delete old `ActionSystemTest` files

5 files changed, 251 insertions, 0 deletions

diff --git a/actionpack/lib/action_dispatch/system_test_case.rb b/actionpack/lib/action_dispatch/system_test_case.rb
new file mode 100644
index 0000000000..850f101ca8
--- /dev/null
+++ b/actionpack/lib/action_dispatch/system_test_case.rb
@@ -0,0 +1,129 @@
+require "capybara/dsl"
+require "action_controller"
+require "action_dispatch/system_testing/driver"
+require "action_dispatch/system_testing/server"
+require "action_dispatch/system_testing/browser"
+require "action_dispatch/system_testing/test_helpers/screenshot_helper"
+
+module ActionDispatch
+  class SystemTestCase < IntegrationTest
+    # = System Testing
+    #
+    # System tests let you test real application in the browser. Because system
+    # tests use a real browser experience you can test all of your JavaScript
+    # easily from your test suite.
+    #
+    # To create a system test in your application, extend your test class
+    # from <tt>ApplicationSystemTestCase</tt>. System tests use Capybara as a
+    # base and allow you to configure the settings through your
+    # <tt>system_test_helper.rb</tt> file that is generated with a new
+    # application or scaffold.
+    #
+    # Here is an example system test:
+    #
+    #   require 'system_test_helper'
+    #
+    #   class Users::CreateTest < ApplicationSystemTestCase
+    #     test "adding a new user" do
+    #       visit users_path
+    #       click_on 'New User'
+    #
+    #       fill_in 'Name', with: 'Arya'
+    #       click_on 'Create User'
+    #
+    #       assert_text 'Arya'
+    #     end
+    #   end
+    #
+    # When generating an application or scaffold a +system_test_helper.rb+ will also
+    # be generated containing the base class for system testing. This is where you
+    # can change the driver, add Capybara settings, and other configuration for
+    # your system tests.
+    #
+    #   require "test_helper"
+    #
+    #   class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
+    #     teardown do
+    #       take_failed_screenshot
+    #       Capybara.reset_sessions!
+    #     end
+    #   end
+    #
+    # By default, <tt>ActionDispatch::SystemTestCase</tt> is driven by the
+    # Selenium driver, with the Chrome browser, and a browser size of 1400x1400.
+    #
+    # Changing the driver configuration options are easy. Let's say you want to use
+    # and the Firefox browser instead. In your +system_test_helper.rb+
+    # file add the following:
+    #
+    #   require "test_helper"
+    #
+    #   class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
+    #     driven_by :selenium, using: :firefox
+    #
+    #     teardown do
+    #       take_failed_screenshot
+    #       Capybara.reset_sessions!
+    #     end
+    #   end
+    #
+    # +driven_by+ has a required argument for the driver name. The keyword
+    # arguments are +:using+ for the browser (not applicable for headless drivers),
+    # and +:screen_size+ to change the size of the screen taking screenshots.
+    #
+    # To use a headless driver, like Poltergeist, update your Gemfile to use
+    # Poltergeist instead of Selenium and then declare the driver name in the
+    # +system_test_helper.rb+ file. In this case you would leave out the +:using+
+    # option because the driver is headless.
+    #
+    #   require "test_helper"
+    #   require "capybara/poltergeist"
+    #
+    #   class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
+    #     driven_by :poltergeist
+    #
+    #     teardown do
+    #       take_failed_screenshot
+    #       Capybara.reset_sessions!
+    #     end
+    #   end
+    #
+    # Because <tt>ActionDispatch::SystemTestCase</tt> is a shim between Capybara
+    # and Rails, any driver that is supported by Capybara is supported by system
+    # tests as long as you include the required gems and files.
+    include Capybara::DSL
+    include SystemTesting::TestHelpers::ScreenshotHelper
+
+    def self.start_application # :nodoc:
+      Capybara.app = Rack::Builder.new do
+        map "/" do
+          run Rails.application
+        end
+      end
+    end
+
+    # System Test configuration options
+    #
+    # The defaults settings are Selenium, using Chrome, with a screen size
+    # of 1400x1400.
+    #
+    # Examples:
+    #
+    #   driven_by :poltergeist
+    #
+    #   driven_by :selenium, using: :firefox
+    #
+    #   driven_by :selenium, screen_size: [800, 800]
+    def self.driven_by(driver, using: :chrome, screen_size: [1400, 1400])
+      SystemTesting::Driver.new(driver).run
+      SystemTesting::Server.new.run
+      SystemTesting::Browser.new(using, screen_size).run if selenium?(driver)
+    end
+
+    def self.selenium?(driver) # :nodoc:
+      driver == :selenium
+    end
+  end
+
+  SystemTestCase.start_application
+end
diff --git a/actionpack/lib/action_dispatch/system_testing/browser.rb b/actionpack/lib/action_dispatch/system_testing/browser.rb
new file mode 100644
index 0000000000..c9a6628516
--- /dev/null
+++ b/actionpack/lib/action_dispatch/system_testing/browser.rb
@@ -0,0 +1,28 @@
+module ActionDispatch
+  module SystemTesting
+    class Browser # :nodoc:
+      def initialize(name, screen_size)
+        @name = name
+        @screen_size = screen_size
+      end
+
+      def run
+        register
+        setup
+      end
+
+      private
+        def register
+          Capybara.register_driver @name do |app|
+            Capybara::Selenium::Driver.new(app, browser: @name).tap do |driver|
+              driver.browser.manage.window.size = Selenium::WebDriver::Dimension.new(*@screen_size)
+            end
+          end
+        end
+
+        def setup
+          Capybara.default_driver = @name.to_sym
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/system_testing/driver.rb b/actionpack/lib/action_dispatch/system_testing/driver.rb
new file mode 100644
index 0000000000..7c2ad84e19
--- /dev/null
+++ b/actionpack/lib/action_dispatch/system_testing/driver.rb
@@ -0,0 +1,18 @@
+module ActionDispatch
+  module SystemTesting
+    class Driver # :nodoc:
+      def initialize(name)
+        @name = name
+      end
+
+      def run
+        register
+      end
+
+      private
+        def register
+          Capybara.default_driver = @name
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/system_testing/server.rb b/actionpack/lib/action_dispatch/system_testing/server.rb
new file mode 100644
index 0000000000..62ba07736b
--- /dev/null
+++ b/actionpack/lib/action_dispatch/system_testing/server.rb
@@ -0,0 +1,23 @@
+require "rack/handler/puma"
+
+module ActionDispatch
+  module SystemTesting
+    class Server # :nodoc:
+      def run
+        register
+        setup
+      end
+
+      private
+        def register
+          Capybara.register_server :rails_puma do |app, port, host|
+            Rack::Handler::Puma.run(app, Port: port, Threads: "0:1")
+          end
+        end
+
+        def setup
+          Capybara.server = :rails_puma
+        end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb b/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb
new file mode 100644
index 0000000000..1ad64b7f78
--- /dev/null
+++ b/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb
@@ -0,0 +1,53 @@
+module ActionDispatch
+  module SystemTesting
+    module TestHelpers
+      # Screenshot helper for system testing
+      module ScreenshotHelper
+        # Takes a screenshot of the current page in the browser.
+        #
+        # +take_screenshot+ can be used at any point in your system tests to take
+        # a screenshot of the current state. This can be useful for debugging or
+        # automating visual testing.
+        def take_screenshot
+          save_image
+          puts "[Screenshot]: #{image_path}"
+          puts display_image
+        end
+
+        # Takes a screenshot of the current page in the browser if the test
+        # failed.
+        #
+        # +take_screenshot+ is included in <tt>system_test_helper.rb</tt> that is
+        # generated with the application. To take screenshots when a test fails
+        # add +take_failed_screenshot+ to the teardown block before clearing
+        # sessions.
+        def take_failed_screenshot
+          take_screenshot unless passed?
+        end
+
+        private
+          def image_path
+            "tmp/screenshots/failures_#{method_name}.png"
+          end
+
+          def save_image
+            page.save_screenshot(Rails.root.join(image_path))
+          end
+
+          def display_image
+            if ENV["CAPYBARA_INLINE_SCREENSHOT"] == "artifact"
+              "\e]1338;url=artifact://#{image_path}\a"
+            else
+              name = inline_base64(File.basename(image_path))
+              image = inline_base64(File.read(image_path))
+              "\e]1337;File=name=#{name};height=400px;inline=1:#{image}\a"
+            end
+          end
+
+          def inline_base64(path)
+            Base64.encode64(path).gsub("\n", "")
+          end
+      end
+    end
+  end
+end