Test how manager should handle destroyed windows

lib/uh/wm/testing/acceptance_helpers.rb

@@ -106,6 +106,11 @@ module Uh
           x_client(options).sync
         end
 
+        def x_window_destroy **options
+          x_client(options).destroy
+          x_client(options).sync
+        end
+
         def x_clients_ensure_stop
           @x_clients and @x_clients.any? and @x_clients.values.each &:terminate
         end
@@ -177,6 +182,11 @@ module Uh
             window.unmap
             self
           end
+
+          def destroy
+            window.destroy
+            self
+          end
         end
       end
     end