"use strict"; var uniqueName = "bug 465215"; var uniqueValue1 = "as good as unique: " + Date.now(); var uniqueValue2 = "as good as unique: " + Math.random(); add_task(function* () { // set a unique value on a new, blank tab let tab1 = gBrowser.addTab("about:blank"); yield promiseBrowserLoaded(tab1.linkedBrowser); ss.setTabValue(tab1, uniqueName, uniqueValue1); // duplicate the tab with that value let tab2 = ss.duplicateTab(window, tab1); yield promiseTabRestored(tab2); is(ss.getTabValue(tab2, uniqueName), uniqueValue1, "tab value was duplicated"); ss.setTabValue(tab2, uniqueName, uniqueValue2); isnot(ss.getTabValue(tab1, uniqueName), uniqueValue2, "tab values aren't sync'd"); // overwrite the tab with the value which should remove it yield promiseTabState(tab1, {entries: []}); is(ss.getTabValue(tab1, uniqueName), "", "tab value was cleared"); // clean up gBrowser.removeTab(tab2); gBrowser.removeTab(tab1); });