1 files changed, 13 insertions, 2 deletions
diff --git a/actionpack/lib/action_dispatch/system_testing/driver.rb b/actionpack/lib/action_dispatch/system_testing/driver.rb
index 770fbde74e..280989a146 100644
--- a/actionpack/lib/action_dispatch/system_testing/driver.rb
+++ b/actionpack/lib/action_dispatch/system_testing/driver.rb
@@ -38,13 +38,24 @@ module ActionDispatch
             browser_options.args << "--disable-gpu"
 
             @options.merge(options: browser_options)
+          elsif @browser == :headless_firefox
+            browser_options = Selenium::WebDriver::Firefox::Options.new
+            browser_options.args << "-headless"
+
+            @options.merge(options: browser_options)
           else
             @options
           end
         end
 
         def browser
-          @browser == :headless_chrome ? :chrome : @browser
+          if @browser == :headless_chrome
+            :chrome
+          elsif @browser == :headless_firefox
+            :firefox
+          else
+            @browser
+          end
         end
 
         def register_selenium(app)
@@ -59,7 +70,7 @@ module ActionDispatch
 
         def register_webkit(app)
           Capybara::Webkit::Driver.new(app, Capybara::Webkit::Configuration.to_hash.merge(@options)).tap do |driver|
-            driver.resize_window(*@screen_size)
+            driver.resize_window_to(driver.current_window_handle, *@screen_size)
           end
         end