# Instructions

- Following Playwright test failed.
- Explain why, be concise, respect Playwright best practices.
- Provide a snippet of code with the fix, if possible.

# Test info

- Name: verify_stress.spec.js >> Stress test: Virtual List should handle 10,000 items with dynamic height
- Location: test/verify_stress.spec.js:3:1

# Error details

```
Test timeout of 60000ms exceeded.
```

```
Error: page.waitForFunction: Test timeout of 60000ms exceeded.
```

# Page snapshot

```yaml
- generic [ref=e2]:
  - heading "1. Standard List (Normal)" [level=5] [ref=e4]
  - 'heading "2. Group List (Mode: Group)" [level=5] [ref=e7]'
  - 'heading "3. Tree List (Mode: Tree + Collapsible)" [level=5] [ref=e10]'
  - heading "4. FAST Virtual List (10,000 Items + Dynamic Height)" [level=5] [ref=e13]
```

# Test source

```ts
  1  | import { test, expect } from '@playwright/test';
  2  | 
  3  | test('Stress test: Virtual List should handle 10,000 items with dynamic height', async ({ page }) => {
  4  |     test.setTimeout(60000); 
  5  |     page.on('console', msg => console.log('BROWSER LOG:', msg.text()));
  6  |     
  7  |     await page.goto('http://localhost:8082/test/list_test.html');
  8  |     
  9  |     const listFast = page.locator('#listFast');
  10 |     await expect(listFast).toBeVisible();
> 11 |     await page.waitForFunction(() => document.querySelectorAll('#listFast .list-group-item').length > 0);
     |                ^ Error: page.waitForFunction: Test timeout of 60000ms exceeded.
  12 |     
  13 |     // Check initial state
  14 |     const scrollTop = await listFast.evaluate(e => e.scrollTop);
  15 |     const scrollHeight = await listFast.evaluate(e => e.scrollHeight);
  16 |     const clientHeight = await listFast.evaluate(e => e.clientHeight);
  17 |     console.log(`Initial: scrollTop=${scrollTop}, scrollHeight=${scrollHeight}, clientHeight=${clientHeight}`);
  18 |     
  19 |     // Attach event listener to see if scroll fires
  20 |     await listFast.evaluate(e => {
  21 |         e.addEventListener('scroll', () => console.log('SCROLL EVENT FIRED! new scrollTop:', e.scrollTop));
  22 |     });
  23 | 
  24 |     // Scroll to the very end
  25 |     await listFast.evaluate(e => e.scrollTop = e.scrollHeight);
  26 |     await page.waitForTimeout(1000);
  27 |     
  28 |     const finalScrollTop = await listFast.evaluate(e => e.scrollTop);
  29 |     console.log(`Final: scrollTop=${finalScrollTop}`);
  30 |     
  31 |     const lastItemText = await listFast.locator('.list-group-item').last().textContent();
  32 |     console.log('Last rendered item text:', lastItemText);
  33 |     expect(lastItemText).toContain('Virtual Item 10000');
  34 | });
  35 | 
```