Rename methods and update docs

This is a minor update to the named methods for the following:

- s/desired_capabilities/capabilities
- s/driver_options/capabilities

Since they are all the same thing we should keep the name the same
throughout the feature.

Updated docs to match / be a little bit clearer

Also updated the Gemfile for selenium-webdriver.

Gemfile.lock

@@ -238,10 +238,10 @@ GEM
     faye-websocket (0.10.7)
       eventmachine (>= 0.12.0)
       websocket-driver (>= 0.5.1)
-    ffi (1.9.25)
-    ffi (1.9.25-java)
-    ffi (1.9.25-x64-mingw32)
-    ffi (1.9.25-x86-mingw32)
+    ffi (1.10.0)
+    ffi (1.10.0-java)
+    ffi (1.10.0-x64-mingw32)
+    ffi (1.10.0-x86-mingw32)
     fugit (1.1.6)
       et-orbi (~> 1.1, >= 1.1.6)
       raabro (~> 1.1)
@@ -336,6 +336,7 @@ GEM
     mysql2 (0.5.2-x64-mingw32)
     mysql2 (0.5.2-x86-mingw32)
     nio4r (2.3.1)
+    nio4r (2.3.1-java)
     nokogiri (1.9.1)
       mini_portile2 (~> 2.4.0)
     nokogiri (1.9.1-java)
@@ -432,9 +433,9 @@ GEM
       tilt (>= 1.1, < 3)
     sdoc (1.0.0)
       rdoc (>= 5.0)
-    selenium-webdriver (3.141.0)
+    selenium-webdriver (3.5.2)
       childprocess (~> 0.5)
-      rubyzip (~> 1.2, >= 1.2.2)
+      rubyzip (~> 1.0)
     sequel (5.14.0)
     serverengine (2.0.7)
       sigdump (~> 0.2.2)
@@ -509,6 +510,8 @@ GEM
     websocket (1.2.8)
     websocket-driver (0.7.0)
       websocket-extensions (>= 0.1.0)
+    websocket-driver (0.7.0-java)
+      websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.3)
     xpath (3.2.0)
       nokogiri (~> 1.8)

actionpack/lib/action_dispatch/system_test_case.rb

@@ -89,12 +89,16 @@ module ActionDispatch
   #       { js_errors: true }
   #   end
   #
-  # Most drivers won't let you add specific browser capabilities through the +options+ mentioned above.
-  # As an example, if you want to add mobile emulation on chrome, you'll have to create an instance of selenium's
-  # `Chrome::Options` object and add capabilities to it.
-  # To make things easier, `driven_by` can be called with a block.
-  # The block will be passed an instance of `<Driver>::Options` where you can define the capabilities you want.
-  # Please refer to your driver documentation to learn about supported options.
+  # Some drivers require browser capabilities to be passed as a block instead
+  # of through the +options+ hash.
+  #
+  # As an example, if you want to add mobile emulation on chrome, you'll have to
+  # create an instance of selenium's `Chrome::Options` object and add
+  # capabilities with a block.
+  #
+  # The block will be passed an instance of `<Driver>::Options` where you can
+  # define the capabilities you want. Please refer to your driver documentation
+  # to learn about supported options.
   #
   # class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
   #   driven_by :chrome, screen_size: [1024, 768] do |driver_option|
@@ -148,10 +152,10 @@ module ActionDispatch
     #   driven_by :selenium, using: :firefox
     #
     #   driven_by :selenium, using: :headless_firefox
-    def self.driven_by(driver, using: :chrome, screen_size: [1400, 1400], options: {}, &desired_capabilities)
+    def self.driven_by(driver, using: :chrome, screen_size: [1400, 1400], options: {}, &capabilities)
       driver_options = { using: using, screen_size: screen_size, options: options }
 
-      self.driver = SystemTesting::Driver.new(driver, driver_options, &desired_capabilities)
+      self.driver = SystemTesting::Driver.new(driver, driver_options, &capabilities)
     end
 
     driven_by :selenium

actionpack/lib/action_dispatch/system_testing/browser.rb

@@ -29,7 +29,7 @@ module ActionDispatch
         end
       end
 
-      def driver_options
+      def capabilities
         @option ||= case type
                     when :chrome
                       Selenium::WebDriver::Chrome::Options.new
@@ -40,16 +40,16 @@ module ActionDispatch
 
       private
         def headless_chrome_browser_options
-          driver_option.args << "--headless"
-          driver_option.args << "--disable-gpu" if Gem.win_platform?
+          capability.args << "--headless"
+          capability.args << "--disable-gpu" if Gem.win_platform?
 
-          driver_options
+          capabilities
         end
 
         def headless_firefox_browser_options
-          driver_options.args << "-headless"
+          capabilities.args << "-headless"
 
-          driver_options
+          capabilities
         end
     end
   end

actionpack/lib/action_dispatch/system_testing/driver.rb

@@ -3,12 +3,12 @@
 module ActionDispatch
   module SystemTesting
     class Driver # :nodoc:
-      def initialize(name, **options, &desired_capabilities)
+      def initialize(name, **options, &capabilities)
         @name = name
         @browser = Browser.new(options[:using])
         @screen_size = options[:screen_size]
         @options = options[:options]
-        @desired_capabilities = desired_capabilities
+        @capabilities = capabilities
       end
 
       def use
@@ -23,7 +23,7 @@ module ActionDispatch
         end
 
         def register
-          define_browser_capabilities(@browser.driver_options)
+          define_browser_capabilities(@browser.capabilities)
 
           Capybara.register_driver @name do |app|
             case @name
@@ -34,8 +34,8 @@ module ActionDispatch
           end
         end
 
-        def define_browser_capabilities(driver_options)
-          @desired_capabilities.call(driver_options) if @desired_capabilities
+        def define_browser_capabilities(capabilities)
+          @capabilities.call(capabilities) if @capabilities
         end
 
         def browser_options

railties/test/application/test_runner_test.rb

@@ -771,6 +771,7 @@ module ApplicationTests
     def test_reset_sessions_on_failed_system_test_screenshot
       app_file "test/system/reset_sessions_on_failed_system_test_screenshot_test.rb", <<~RUBY
         require "application_system_test_case"
+        require "selenium/webdriver"
 
         class ResetSessionsOnFailedSystemTestScreenshotTest < ApplicationSystemTestCase
           ActionDispatch::SystemTestCase.class_eval do