feat: backport command callbacks testing

Author: palkan

lib/anycable/rails/action_cable_ext/connection.rb

@@ -48,10 +48,43 @@ def around_command(*methods, &block)
   end)
 
   ActionCable::Connection::Base.prepend(Module.new do
-    def dispatch_websocket_message(*)
+    def dispatch_websocket_message(websocket_message)
       return super unless websocket.alive?
 
-      run_callbacks(:command) { super }
+      handle_channel_command(decode(websocket_message))
+    end
+
+    def handle_channel_command(payload)
+      run_callbacks :command do
+        subscriptions.execute_command payload
+      end
+    end
+  end)
+end
+
+# Trigger autoload
+test_case_defined = false
+
+begin
+  ActionCable::Connection::TestCase # rubocop:disable Lint/Void
+  test_case_defined = true
+rescue NameError
+end
+
+# Backport: https://github.com/rails/rails/pull/45445
+if test_case_defined && !ActionCable::Connection::TestConnection.method_defined?(:transmissions)
+  ActionCable::Connection::TestConnection.prepend(Module.new do
+    attr_reader :transmissions
+
+    def initialize(*)
+      super
+
+      @transmissions = []
+      @subscriptions = ActionCable::Connection::Subscriptions.new(self)
+    end
+
+    def transmit(cable_message)
+      transmissions << cable_message.with_indifferent_access
     end
   end)
 end

spec/integrations/action_cable_testing_spec.rb

@@ -65,5 +65,19 @@ def connection_class
 
       expect(ApplicationCable::Connection.events_log.last.fetch(:data)).to eq(name: "max", url: "http://test.host/cable?token=123")
     end
+
+    specify "callbacks" do
+      connect "/cable?token=123", session: {username: user.name}
+
+      connection.handle_channel_command(
+        {
+          "identifier" => {channel: "ChatChannel"}.to_json,
+          "command" => "subscribe"
+        }
+      )
+
+      expect(connection.transmissions.last["type"]).to eq("confirm_subscription")
+      expect(ApplicationCable::Connection.events_log.last[:source]).to eq "command"
+    end
   end
 end