1 files changed, 63 insertions, 0 deletions
diff --git a/toolkit/components/reader/test/head.js b/toolkit/components/reader/test/head.js
new file mode 100644
index 0000000000..6a8e09ecb2
--- /dev/null
+++ b/toolkit/components/reader/test/head.js
@@ -0,0 +1,63 @@
+ChromeUtils.defineESModuleGetters(this, {
+  PromiseUtils: "resource://gre/modules/PromiseUtils.sys.mjs",
+});
+
+/* exported promiseTabLoadEvent, is_element_visible, is_element_hidden */
+
+/**
+ * Waits for a load (or custom) event to finish in a given tab. If provided
+ * load an uri into the tab.
+ *
+ * @param tab
+ *        The tab to load into.
+ * @param [optional] url
+ *        The url to load, or the current url.
+ * @return {Promise} resolved when the event is handled.
+ * @resolves to the received event
+ * @rejects if a valid load event is not received within a meaningful interval
+ */
+function promiseTabLoadEvent(tab, url) {
+  let deferred = PromiseUtils.defer();
+  info("Wait tab event: load");
+
+  function handle(loadedUrl) {
+    if (loadedUrl === "about:blank" || (url && loadedUrl !== url)) {
+      info(`Skipping spurious load event for ${loadedUrl}`);
+      return false;
+    }
+
+    info("Tab event received: load");
+    return true;
+  }
+
+  // Create two promises: one resolved from the content process when the page
+  // loads and one that is rejected if we take too long to load the url.
+  let loaded = BrowserTestUtils.browserLoaded(tab.linkedBrowser, false, handle);
+
+  let timeout = setTimeout(() => {
+    deferred.reject(new Error("Timed out while waiting for a 'load' event"));
+  }, 30000);
+
+  loaded.then(() => {
+    clearTimeout(timeout);
+    deferred.resolve();
+  });
+
+  if (url) {
+    BrowserTestUtils.loadURIString(tab.linkedBrowser, url);
+  }
+
+  // Promise.all rejects if either promise rejects (i.e. if we time out) and
+  // if our loaded promise resolves before the timeout, then we resolve the
+  // timeout promise as well, causing the all promise to resolve.
+  return Promise.all([deferred.promise, loaded]);
+}
+
+function is_element_visible(element, msg) {
+  isnot(element, null, "Element should not be null, when checking visibility");
+  ok(BrowserTestUtils.is_visible(element), msg || "Element should be visible");
+}
+function is_element_hidden(element, msg) {
+  isnot(element, null, "Element should not be null, when checking visibility");
+  ok(BrowserTestUtils.is_hidden(element), msg || "Element should be hidden");
+}