Bug 1625942: Add a browser test for document events ResourceWatcher. r=ochameau

Depends on D69329

Differential Revision: https://phabricator.services.mozilla.com/D71007

devtools/shared/resources/tests/browser.ini

@@ -12,6 +12,7 @@ support-files =
   test_worker.js
 
 [browser_resources_console_messages.js]
+[browser_resources_document_events.js]
 [browser_target_list_frames.js]
 [browser_target_list_preffedoff.js]
 [browser_target_list_processes.js]

devtools/shared/resources/tests/browser_resources_document_events.js

@@ -0,0 +1,103 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test the ResourceWatcher API around DOCUMENT_EVENTS
+
+const { TargetList } = require("devtools/shared/resources/target-list");
+const {
+  ResourceWatcher,
+} = require("devtools/shared/resources/resource-watcher");
+
+add_task(async function() {
+  // Open a test tab
+  const tab = await addTab("data:text/html,Document Events");
+
+  // Create a TargetList for the test tab
+  const client = await createLocalClient();
+  const target = await client.mainRoot.getTab({ tab });
+  const targetList = new TargetList(client.mainRoot, target);
+  await targetList.startListening();
+
+  // Activate ResourceWatcher
+  const listener = new ResourceListener();
+  const resourceWatcher = new ResourceWatcher(targetList);
+
+  info(
+    "Check whether the document events are fired correctly even when the document was already loaded"
+  );
+  const onLoadingAtInit = listener.once("dom-loading");
+  const onInteractiveAtInit = listener.once("dom-interactive");
+  const onCompleteAtInit = listener.once("dom-complete");
+  await resourceWatcher.watch(
+    [ResourceWatcher.TYPES.DOCUMENT_EVENTS],
+    parameters => listener.dispatch(parameters)
+  );
+  await assertEvents(onLoadingAtInit, onInteractiveAtInit, onCompleteAtInit);
+  ok(
+    true,
+    "Document events are fired even when the document was already loaded"
+  );
+
+  info("Check whether the document events are fired correctly when reloading");
+  const onLoadingAtReloaded = listener.once("dom-loading");
+  const onInteractiveAtReloaded = listener.once("dom-interactive");
+  const onCompleteAtReloaded = listener.once("dom-complete");
+  gBrowser.reloadTab(tab);
+  await assertEvents(
+    onLoadingAtReloaded,
+    onInteractiveAtReloaded,
+    onCompleteAtReloaded
+  );
+  ok(true, "Document events are fired after reloading");
+
+  await targetList.stopListening();
+  await client.close();
+});
+
+async function assertEvents(onLoading, onInteractive, onComplete) {
+  const loadingEvent = await onLoading;
+  const interactiveEvent = await onInteractive;
+  const completeEvent = await onComplete;
+  is(
+    typeof loadingEvent.time,
+    "number",
+    "Type of time attribute for loading event is correct"
+  );
+  is(
+    typeof interactiveEvent.time,
+    "number",
+    "Type of time attribute for interactive event is correct"
+  );
+  is(
+    typeof completeEvent.time,
+    "number",
+    "Type of time attribute for complete event is correct"
+  );
+
+  ok(
+    loadingEvent.time < interactiveEvent.time,
+    "Timestamp for interactive event is greater than loading event"
+  );
+  ok(
+    interactiveEvent.time < completeEvent.time,
+    "Timestamp for complete event is greater than interactive event"
+  );
+}
+
+class ResourceListener {
+  _listeners = new Map();
+
+  dispatch({ resourceType, targetFront, resource }) {
+    const resolve = this._listeners.get(resource.name);
+    if (resolve) {
+      resolve(resource);
+      this._listeners.delete(resource.name);
+    }
+  }
+
+  once(resourceName) {
+    return new Promise(r => this._listeners.set(resourceName, r));
+  }
+}