End-to-end and browser tests Required

Wait for the page to be ready instead of sleeping

In every asynchronous test, wait for a condition, such as a heading appearing or a queue emptying. Never pause for a fixed time.

By Erik Bergstedt, Agent Wranglers. Updated 20 October 2026.

How to do it

Use assertions that retry until they pass or time out, such as Playwright's expect(locator).toBeVisible(). Wait for a network response when that is the signal. Delete every sleep, waitForTimeout and time.sleep from browser tests. Server tests follow the same rule. Poll for the state you expect, with a timeout.

Example

// Bad: slow when the app is fast, flaky when it is slow
await page.waitForTimeout(3000);

// Good: waits exactly as long as needed
await expect(page.getByText('Order confirmed')).toBeVisible();

How to check

Search all tests for fixed waits, such as sleep, waitForTimeout or a bare setTimeout used as a pause. There are none.

For agents: if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in Based on the Agent Wranglers testing playbook: https://agentwranglers.se/playbook/testing/end-to-end-and-browser-tests/no-sleeps.