Add configuration option for driver adapter

This allows any application to change the driver adapter based on the
config settings in the test env.

3 files changed, 18 insertions, 4 deletions

diff --git a/actionpack/lib/system_testing/base.rb b/actionpack/lib/system_testing/base.rb
index ae4236f97d..770342da82 100644
--- a/actionpack/lib/system_testing/base.rb
+++ b/actionpack/lib/system_testing/base.rb
@@ -5,5 +5,7 @@ module SystemTesting
   module Base
     include TestHelper
     include DriverAdapter
+
+    ActiveSupport.run_load_hooks(:system_testing, self)
   end
 end
diff --git a/actionpack/lib/system_testing/driver_adapter.rb b/actionpack/lib/system_testing/driver_adapter.rb
index 70c4396323..6d94582395 100644
--- a/actionpack/lib/system_testing/driver_adapter.rb
+++ b/actionpack/lib/system_testing/driver_adapter.rb
@@ -4,11 +4,9 @@ module SystemTesting
   module DriverAdapter
     extend ActiveSupport::Concern
 
-    included do
-      self.driver_adapter = :capybara_rack_test_driver
-    end
-
     module ClassMethods
+      attr_accessor :driver_adapter
+
       def driver_adapter=(driver_name_or_class)
         driver = DriverAdapters.lookup(driver_name_or_class).new
         driver.call
diff --git a/actionpack/lib/system_testing/railtie.rb b/actionpack/lib/system_testing/railtie.rb
new file mode 100644
index 0000000000..aa3df29344
--- /dev/null
+++ b/actionpack/lib/system_testing/railtie.rb
@@ -0,0 +1,14 @@
+module SystemTesting
+  class Railtie < Rails::Railtie
+    config.system_testing = ActiveSupport::OrderedOptions.new
+
+    initializer "system_testing.set_configs" do |app|
+      options = app.config.system_testing
+      options.driver_adapter ||= :capybara_rack_test_driver
+
+      ActiveSupport.on_load(:system_testing) do
+        options.each { |k,v| send("#{k}=", v) }
+      end
+    end
+  end
+end