Bug 1141041 - Add test to ensure that updating the Page Style menu works. r=jaws

browser/base/content/test/general/browser.ini

@@ -345,6 +345,7 @@ skip-if = buildapp == 'mulet' || e10s # Bug 1093603 - test breaks with PopupNoti
 [browser_pageInfo.js]
 skip-if = buildapp == 'mulet'
 [browser_page_style_menu.js]
+[browser_page_style_menu_update.js]
 [browser_parsable_css.js]
 [browser_parsable_script.js]
 skip-if = asan || (os == 'linux' && !debug && (bits == 32)) # disabled on asan because of timeouts, and bug 1172468 for the linux 32-bit pgo issue.

browser/base/content/test/general/browser_page_style_menu_update.js

@@ -0,0 +1,68 @@
+"use strict";
+
+const PAGE = "http://example.com/browser/browser/base/content/test/general/page_style_sample.html";
+
+/**
+ * Stylesheets are updated for a browser after the pageshow event.
+ * This helper function returns a Promise that waits for that pageshow
+ * event, and then resolves on the next tick to ensure that gPageStyleMenu
+ * has had a chance to update the stylesheets.
+ *
+ * @param browser
+ *        The <xul:browser> to wait for.
+ * @return Promise
+ */
+function promiseStylesheetsUpdated(browser) {
+  return ContentTask.spawn(browser, { PAGE }, function*(args) {
+    return new Promise((resolve) => {
+      addEventListener("pageshow", function onPageShow(e) {
+        if (e.target.location == args.PAGE) {
+          removeEventListener("pageshow", onPageShow);
+          content.setTimeout(resolve, 0);
+        }
+      });
+    })
+  });
+}
+
+/**
+ * Tests that the Page Style menu shows the currently
+ * selected Page Style after a new one has been selected.
+ */
+add_task(function*() {
+  let tab = yield BrowserTestUtils.openNewForegroundTab(gBrowser, "about:blank", false);
+  let browser = tab.linkedBrowser;
+
+  yield BrowserTestUtils.loadURI(browser, PAGE);
+  yield promiseStylesheetsUpdated(browser);
+
+  let menupopup = document.getElementById("pageStyleMenu").menupopup;
+  gPageStyleMenu.fillPopup(menupopup);
+
+  // page_style_sample.html should default us to selecting the stylesheet
+  // with the title "6" first.
+  let selected = menupopup.querySelector("menuitem[checked='true']");
+  is(selected.getAttribute("label"), "6", "Should have '6' stylesheet selected by default");
+
+  // Now select stylesheet "1"
+  let targets = menupopup.querySelectorAll("menuitem");
+  let target = menupopup.querySelector("menuitem[label='1']");
+  target.click();
+
+  // Now we need to wait for the content process to send its stylesheet
+  // update for the selected tab to the parent. Because messages are
+  // guaranteed to be sent in order, we'll make sure we do the check
+  // after the parent has been updated by yielding until the child
+  // has finished running a ContentTask for us.
+  yield ContentTask.spawn(browser, {}, function*() {
+    dump('\nJust wasting some time.\n');
+  });
+
+  gPageStyleMenu.fillPopup(menupopup);
+  // gPageStyleMenu empties out the menu between opens, so we need
+  // to get a new reference to the selected menuitem
+  selected = menupopup.querySelector("menuitem[checked='true']");
+  is(selected.getAttribute("label"), "1", "Should now have stylesheet 1 selected");
+
+  yield BrowserTestUtils.removeTab(tab);
+});