chore: add test

__tests__/e2e/markdown-extensions/index.md

@@ -120,6 +120,12 @@ const line1 = 'This is line 1'
 const line2 = 'This is line 2'
 ```
 
+## Title Bar
+
+```js [main.js]
+console.log('Hello, VitePress!')
+```
+
 ## Import Code Snippets
 
 ### Basic Code Snippet

__tests__/e2e/markdown-extensions/markdown-extensions.test.ts

@@ -84,6 +84,7 @@ describe('Table of Contents', () => {
         "Multiple single lines, ranges",
         "Comment Highlight",
         "Line Numbers",
+        "Title Bar",
         "Import Code Snippets",
         "Basic Code Snippet",
         "Specify Region",
@@ -213,6 +214,16 @@ describe('Line Numbers', () => {
   })
 })
 
+describe('Title bar', () => {
+  test('render title bar', async () => {
+    const div = page.locator('#title-bar + div')
+    const titleBar = div.locator('.title-bar')
+    expect(titleBar).toBeTruthy()
+    const titleText = titleBar.locator('.title-text')
+    expect(await titleText.textContent()).toBe('main.js')
+  })
+})
+
 describe('Import Code Snippets', () => {
   test('basic', async () => {
     const lines = page.locator('#basic-code-snippet + div code > span')