target0, "pointerup", function (event) {
                    let pointerdown_event = pointerdown_events.get(event.pointerId);
                    test_pointerEvent.step(function () {
                        assert_true(!!pointerdown_event, "pointerdown event was received.");
                        assert_true(!!pointermove_events.size, "pointermove event was received.");
                        assert_equals(event.pointerId, pointerdown_event.pointerId, "pointerup.pointerId should be the same as pointerdow