add_task(async function () { SpecialPowers.pushPrefEnv({ set: [["layout.spellcheckDefault", 2]] }); let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", { leaveOpen: true, }); is(prefs.selectedPane, "paneGeneral", "General pane was selected"); let doc = gBrowser.contentDocument; let checkbox = doc.querySelector("#checkSpelling"); is( checkbox.checked, Services.prefs.getIntPref("layout.spellcheckDefault") == 2, "checkbox should represent pref value before clicking on checkbox" ); ok( checkbox.checked, "checkbox should be checked before clicking on checkbox" ); checkbox.click(); is( checkbox.checked, Services.prefs.getIntPref("layout.spellcheckDefault") == 2, "checkbox should represent pref value after clicking on checkbox" ); ok( !checkbox.checked, "checkbox should not be checked after clicking on checkbox" ); BrowserTestUtils.removeTab(gBrowser.selectedTab); });