2 files changed, 41 insertions, 0 deletions
diff --git a/actioncable/lib/action_cable/subscription_adapter.rb b/actioncable/lib/action_cable/subscription_adapter.rb
index bcece8d33b..6a9d5c2080 100644
--- a/actioncable/lib/action_cable/subscription_adapter.rb
+++ b/actioncable/lib/action_cable/subscription_adapter.rb
@@ -5,6 +5,7 @@ module ActionCable
     extend ActiveSupport::Autoload
 
     autoload :Base
+    autoload :Test
     autoload :SubscriberMap
     autoload :ChannelPrefix
   end
diff --git a/actioncable/lib/action_cable/subscription_adapter/test.rb b/actioncable/lib/action_cable/subscription_adapter/test.rb
new file mode 100644
index 0000000000..52226a7c71
--- /dev/null
+++ b/actioncable/lib/action_cable/subscription_adapter/test.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require_relative "async"
+
+module ActionCable
+  module SubscriptionAdapter
+    # == Test adapter for Action Cable
+    #
+    # The test adapter should be used only in testing. Along with
+    # <tt>ActionCable::TestHelper</tt> it makes a great tool to test your Rails application.
+    #
+    # To use the test adapter set adapter value to +test+ in your +cable.yml+.
+    #
+    # NOTE: Test adapter extends the <tt>ActionCable::SubscriptionsAdapter::Async</tt> adapter,
+    # so it could be used in system tests too.
+    class Test < Async
+      def broadcast(channel, payload)
+        broadcasts(channel) << payload
+        super
+      end
+
+      def broadcasts(channel)
+        channels_data[channel] ||= []
+      end
+
+      def clear_messages(channel)
+        channels_data[channel] = []
+      end
+
+      def clear
+        @channels_data = nil
+      end
+
+      private
+        def channels_data
+          @channels_data ||= {}
+        end
+    end
+  end
+end