Migrate 'iframed multiple block stylesheets' tests to Playwright (#55003

)

* Migrate 'iframed multiple block stylesheets' tests to Playwright
* Remove old test file

packages/e2e-tests/plugins/iframed-multiple-stylesheets.php

@@ -7,13 +7,6 @@
  * @package gutenberg-test-iframed-multiple-stylesheets
  */
 
-add_action(
-	'setup_theme',
-	static function () {
-		add_theme_support( 'block-templates' );
-	}
-);
-
 add_action(
 	'init',
 	static function () {

test/e2e/specs/editor/plugins/iframed-multiple-block-stylesheets.spec.js

@@ -0,0 +1,42 @@
+/**
+ * WordPress dependencies
+ */
+const { test, expect } = require( '@wordpress/e2e-test-utils-playwright' );
+
+test.describe( 'iframed multiple block stylesheets', () => {
+	test.beforeAll( async ( { requestUtils } ) => {
+		await requestUtils.activatePlugin(
+			'gutenberg-test-iframed-multiple-stylesheets'
+		);
+	} );
+
+	test.beforeEach( async ( { admin } ) => {
+		await admin.createNewPost( { postType: 'page' } );
+	} );
+
+	test.afterAll( async ( { requestUtils } ) => {
+		await requestUtils.deactivatePlugin(
+			'gutenberg-test-iframed-multiple-stylesheets'
+		);
+	} );
+
+	test( 'should load multiple block stylesheets in iframe', async ( {
+		editor,
+	} ) => {
+		await editor.insertBlock( {
+			name: 'test/iframed-multiple-stylesheets',
+		} );
+		const block = editor.canvas.getByRole( 'document', {
+			name: 'Block: Iframed Multiple Stylesheets',
+		} );
+
+		await expect( block ).toBeVisible();
+
+		// Style loaded from the main stylesheet.
+		await expect( block ).toHaveCSS( 'border-style', 'dashed' );
+		// Style loaded from the additional stylesheet.
+		await expect( block ).toHaveCSS( 'border-color', 'rgb(255, 0, 0)' );
+		// Style loaded from the a stylesheet using path instead of handle.
+		await expect( block ).toHaveCSS( 'border-color', 'rgb(255, 0, 0)' );
+	} );
+} );