Fix test failure on ruby head.

Author: samuel-williams-shopify

fixtures/async/container/supervisor/a_monitor.rb

@@ -28,6 +28,8 @@ module Supervisor
 					expect(event).to have_attributes(
 						type: be == :remove,
 					)
+				ensure
+					connection&.close
 				end
 
 				it "can respond to status calls" do
@@ -38,6 +40,8 @@ module Supervisor
 
 					# Maybe we could be a bit more specific.
 					expect(response).to be_a(Array)
+				ensure
+					connection&.close
 				end
 			end
 		end