POC for screenshot when the test errors

[ankur22]

When a test runs, but then fails when we didn't expect it to, the current option for the user is to:

1. Look at the logs;
2. Replicate the issue;
3. Fix the issue.

Another tool that could be useful is the ability to view the page that was rendered when the error occurred. For example, let's say we have the following test:

import { chromium } from 'k6/x/browser'

export default async function () {
  const browser = chromium.launch({ headless: false })
  const context = browser.newContext()
  const page = context.newPage()

  try {
    await page.goto('https://test.k6.io/', { waitUntil: 'networkidle' })
    await Promise.all([
      page.waitForNavigation(),
      page.locator('a[href="/browser.php"]').click(),
    ]);
  } finally {
    page.close()
    browser.close()
  }
}

This test works today. What if the link address changes from browser to browserChrome? Then the test will fail, with a timeout while waiting for the selector a[href="/browser.php"]. What would be good is when the timeout occurs, a screenshot is taken of the current rendered page, which could make it a little easier to identify the problem. This feature could be disabled initially, but enabled with a command line flag and/or env var.