Fix: Flakey deferred store test (WordPress#62571)

* Use events to proceed test when ready

* Initialize once on the event

* Use window not globalThis in test

* Fix event dispatch in page

Co-authored-by: sirreal <jonsurrell@git.wordpress.org>
Co-authored-by: cbravobernal <cbravobernal@git.wordpress.org>

packages/e2e-tests/plugins/interactive-blocks/deferred-store/view.js

@@ -3,8 +3,9 @@
  */
 import { store, getContext } from '@wordpress/interactivity';
 
-document.addEventListener( 'DOMContentLoaded', () => {
-	setTimeout( () => {
+window.addEventListener(
+	'_test_proceed_',
+	() => {
 		store( 'test/deferred-store', {
 			state: {
 				reversedText() {
@@ -16,5 +17,6 @@ document.addEventListener( 'DOMContentLoaded', () => {
 				},
 			},
 		} );
-	}, 100 );
-} );
+	},
+	{ once: true }
+);

test/e2e/specs/interactivity/deferred-store.spec.ts

@@ -21,6 +21,9 @@ test.describe( 'deferred store', () => {
 	} ) => {
 		const resultInput = page.getByTestId( 'result' );
 		await expect( resultInput ).toHaveText( '' );
+		await page.evaluate( () => {
+			window.dispatchEvent( new Event( '_test_proceed_' ) );
+		} );
 		await expect( resultInput ).toHaveText( 'Hello, world!' );
 	} );
 
@@ -31,6 +34,9 @@ test.describe( 'deferred store', () => {
 	} ) => {
 		const resultInput = page.getByTestId( 'result-getter' );
 		await expect( resultInput ).toHaveText( '' );
+		await page.evaluate( () => {
+			window.dispatchEvent( new Event( '_test_proceed_' ) );
+		} );
 		await expect( resultInput ).toHaveText( 'Hello, world!' );
 	} );
 } );