test(playwright): add spyOnEvent for Locators (#25328)

core/src/utils/test/playwright/page/event-spy.ts

@@ -1,3 +1,5 @@
+import type { JSHandle } from '@playwright/test';
+
 import type { E2EPage } from '../playwright-declarations';
 
 /**
@@ -90,15 +92,20 @@ export const initPageEvents = async (page: E2EPage) => {
  * page context to updates the _e2eEvents map
  * when an event is fired.
  */
-export const addE2EListener = async (page: E2EPage, eventName: string, callback: (ev: any) => void) => {
+export const addE2EListener = async (
+  page: E2EPage,
+  elmHandle: JSHandle,
+  eventName: string,
+  callback: (ev: any) => void
+) => {
   const id = page._e2eEventsIds++;
   page._e2eEvents.set(id, {
     eventName,
     callback,
   });
 
-  await page.evaluate(
+  await elmHandle.evaluate(
-    ([eventName, id]) => {
+    (elm, [eventName, id]) => {
       (window as any).stencilSerializeEventTarget = (target: any) => {
         // BROWSER CONTEXT
         if (!target) {
@@ -146,7 +153,7 @@ export const addE2EListener = async (page: E2EPage, eventName: string, callback:
         return serializedEvent;
       };
 
-      window.addEventListener(eventName as string, (ev: Event) => {
+      elm.addEventListener(eventName as string, (ev: Event) => {
         (window as any).ionicOnEvent(id, (window as any).serializeStencilEvent(ev));
       });
     },

core/src/utils/test/playwright/page/utils/index.ts

@@ -4,3 +4,4 @@ export * from './get-snapshot-settings';
 export * from './set-ion-viewport';
 export * from './spy-on-event';
 export * from './set-content';
+export * from './locator';

core/src/utils/test/playwright/page/utils/locator.ts

@@ -0,0 +1,41 @@
+import type { Locator } from '@playwright/test';
+
+import type { E2EPage } from '../../playwright-declarations';
+import { EventSpy, addE2EListener } from '../event-spy';
+
+export type LocatorOptions = {
+  hasText?: string | RegExp;
+  has?: Locator;
+};
+
+export interface E2ELocator extends Locator {
+  /**
+   * Creates a new EventSpy and listens
+   * on the element for an event.
+   * The test will timeout if the event
+   * never fires.
+   *
+   * Usage:
+   * const input = page.locator('ion-input');
+   * const ionChange = await locator.spyOnEvent('ionChange');
+   * ...
+   * await ionChange.next();
+   */
+  spyOnEvent: (eventName: string) => void;
+}
+
+export const locator = (
+  page: E2EPage,
+  originalFn: typeof page.locator,
+  selector: string,
+  options?: LocatorOptions
+): E2ELocator => {
+  const locator = originalFn(selector, options) as E2ELocator;
+  locator.spyOnEvent = async (eventName: string) => {
+    const spy = new EventSpy(eventName);
+    const handle = await locator.evaluateHandle((node: HTMLElement) => node);
+    await addE2EListener(page, handle, eventName, (ev: CustomEvent) => spy.push(ev));
+    return spy;
+  };
+  return locator;
+};

core/src/utils/test/playwright/page/utils/spy-on-event.ts

@@ -4,7 +4,9 @@ import { addE2EListener, EventSpy } from '../event-spy';
 export const spyOnEvent = async (page: E2EPage, eventName: string): Promise<EventSpy> => {
   const spy = new EventSpy(eventName);
 
-  await addE2EListener(page, eventName, (ev: CustomEvent) => spy.push(ev));
+  const handle = await page.evaluateHandle(() => window);
+
+  await addE2EListener(page, handle, eventName, (ev: CustomEvent) => spy.push(ev));
 
   return spy;
 };

core/src/utils/test/playwright/playwright-declarations.ts

@@ -1,6 +1,7 @@
 import type { Page, Response } from '@playwright/test';
 
 import type { EventSpy } from './page/event-spy';
+import type { LocatorOptions, E2ELocator } from './page/utils/locator';
 
 export interface E2EPage extends Page {
   /**
@@ -28,6 +29,13 @@ export interface E2EPage extends Page {
    * [`new URL()`](https://developer.mozilla.org/en-US/docs/Web/API/URL/URL) constructor.
    */
   goto: (url: string) => Promise<null | Response>;
+
+  /**
+   * Find an element by selector.
+   * See https://playwright.dev/docs/locators for more information.
+   */
+  locator: (selector: string, options?: LocatorOptions) => E2ELocator;
+
   /**
    * Increases the size of the page viewport to match the `ion-content` contents.
    * Use this method when taking full-screen screenshots.

core/src/utils/test/playwright/playwright-page.ts

@@ -15,7 +15,9 @@ import {
   setIonViewport,
   spyOnEvent,
   waitForChanges,
+  locator,
 } from './page/utils';
+import type { LocatorOptions } from './page/utils';
 import type { E2EPage } from './playwright-declarations';
 
 type CustomTestArgs = PlaywrightTestArgs &
@@ -32,10 +34,12 @@ type CustomFixtures = {
 export const test = base.extend<CustomFixtures>({
   page: async ({ page }: CustomTestArgs, use: (r: E2EPage) => Promise<void>, testInfo: TestInfo) => {
     const originalGoto = page.goto.bind(page);
+    const originalLocator = page.locator.bind(page);
 
     // Overridden Playwright methods
     page.goto = (url: string) => goToPage(page, url, testInfo, originalGoto);
     page.setContent = (html: string) => setContent(page, html);
+    page.locator = (selector: string, options?: LocatorOptions) => locator(page, originalLocator, selector, options);
     // Custom Ionic methods
     page.getSnapshotSettings = () => getSnapshotSettings(page, testInfo);
     page.setIonViewport = () => setIonViewport(page);