add_task(async function test() { var tab = await BrowserTestUtils.openNewForegroundTab(gBrowser); var gotTabAttrModified = false; var gotTabClose = false; function onTabClose() { gotTabClose = true; tab.addEventListener("TabAttrModified", onTabAttrModified); } function onTabAttrModified() { gotTabAttrModified = true; } tab.addEventListener("TabClose", onTabClose); BrowserTestUtils.removeTab(tab); ok(gotTabClose, "should have got the TabClose event"); ok( !gotTabAttrModified, "shouldn't have got the TabAttrModified event after TabClose" ); tab.removeEventListener("TabClose", onTabClose); tab.removeEventListener("TabAttrModified", onTabAttrModified); });