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Understanding and Fixing Test Failures in Playwright

You might have noticed that your test sometimes fails when clicking a button to open a Bootstrap dialog in Playwright. This is often due to poor page hydration.

What is Page Hydration?

Page hydration refers to the process of sending a static version of the page to the browser first, followed by the dynamic part that makes the page "live". If Playwright starts interacting with the page before it is fully hydrated, issues can arise.

How to Detect Poor Hydration?

To check if your page suffers from poor hydration, you can use Chrome DevTools and emulate a "Slow 3G" network in the Network panel. Reload the page and interact with elements of interest. If button clicks are ignored or entered text is reset, it indicates poor hydration.

How to Fix the Issue?

To fix this, ensure that all interactive controls are disabled until after hydration when the page becomes fully functional.

When clicking an element that triggers multiple navigations in Playwright tests, it is advisable to explicitly wait for a specific URL using page.waitForURL().

import { test } from '@playwright/test';

test('wait for URL', async ({ page }) => {
  await page.goto('https://ray.run/');
  // Clicking a button that triggers navigation
  await page.click('#button-id');
  // Waiting for the specific URL
  await page.waitForURL('https://ray.run/target-url');
});

This ensures that all necessary navigations have completed before proceeding with further actions. By waiting for navigation events to settle down before performing additional interactions or assertions on elements within new documents or pages loaded through navigation events, you can avoid unexpected failures.

Remember, the key is to avoid premature interaction with elements on the page and to wait for all necessary navigations to complete before proceeding with further actions. Happy testing with Playwright!