Migrate Convert Block Type test to Playwright (#42760)

* Migrate Conver Block Type test to Playwright

* Addressed Review Feedbacks

* Fix Stylint Issue

test/e2e/specs/editor/various/convert-block-type.spec.js

@@ -0,0 +1,38 @@
+/**
+ * WordPress dependencies
+ */
+const { test, expect } = require( '@wordpress/e2e-test-utils-playwright' );
+
+test.describe( 'Code block', () => {
+	test.beforeEach( async ( { admin } ) => {
+		await admin.createNewPost();
+	} );
+
+	test.afterEach( async ( { requestUtils } ) => {
+		await requestUtils.deleteAllPosts();
+	} );
+
+	test( 'should convert to a preformatted block', async ( {
+		page,
+		editor,
+	} ) => {
+		const code = 'print "Hello Dolly!"';
+
+		await editor.insertBlock( { name: 'core/code' } );
+		await page.keyboard.type( code );
+
+		// Verify the content starts out as a Code block.
+
+		await expect.poll( editor.getEditedPostContent ).toBe( `<!-- wp:code -->
+<pre class="wp-block-code"><code>${ code }</code></pre>
+<!-- /wp:code -->` );
+
+		await editor.transformBlockTo( 'core/preformatted' );
+
+		// The content should now be a Preformatted block with no data loss.
+		await expect.poll( editor.getEditedPostContent )
+			.toBe( `<!-- wp:preformatted -->
+<pre class="wp-block-preformatted">${ code }</pre>
+<!-- /wp:preformatted -->` );
+	} );
+} );