Quick Debugging Techniques for Playwright Tests

#playwright #testing #debugging #javascript

“Debugging is like being the detective in a crime movie where you are also the murderer.” – Filipe Fortes

Playwright is a powerful tool for end-to-end testing, but debugging test failures can be tricky.

Based on my experience, I’ve put together a practical guide that covers structure, data parsing, configuration, timeouts, and debugging techniques.

Structuring Your Tests

A well-structured test suite makes it easier to locate and fix failing tests.

Keep your tests modular. Use describe blocks to group related tests.
Write reusable helpers for login, navigation, or data entry.
Organize test files by feature (e.g., login.spec.ts, dashboard.spec.ts).

Data Parsing Techniques

Data handling often causes hidden issues. Some tips:

Use JSON.parse() for structured test data and load it from external files.
For CSV data, use libraries like papaparse or csv-parse.
Ensure consistent data types — always cast numbers explicitly when reading from strings.
Use environment variables for sensitive values like credentials.

By standardizing how you parse and use data, you reduce unexpected mismatches during tests.

Configuration Techniques

Playwright offers a central playwright.config.ts file that controls how tests run. Key settings include:

Browsers: Run against multiple browsers by setting projects.
Retries: Add retries for flaky tests with retries: 2.
Reporters: Use html or json reporters for better visibility.
Base URL: Define use: { baseURL: "http://localhost:3000" } to simplify navigation.

Keep configurations consistent across environments using .env files and environment variables.

Handling Timeouts

Timeouts are one of the most common debugging headaches.

Global Timeout: Set in playwright.config.ts with timeout: 30000.
Action Timeout: Control time for specific actions using page.setDefaultTimeout(5000).
Navigation Timeout: Use page.setDefaultNavigationTimeout(10000) to catch slow page loads.

✅ Always prefer await page.waitForSelector() over hard waits like page.waitForTimeout(5000).

Proper timeout management prevents both flaky tests and long waits during failures.

Debugging Techniques

When a test fails, use these approaches to identify the root cause quickly:

Run with npx playwright test --debug to open the inspector.
Use page.pause() inside a test to stop execution and explore manually.
Enable tracing with npx playwright test --trace on to capture screenshots, console logs, and network calls.
Add console.log() statements for critical variables to check runtime values.
Capture video or screenshots on failure by enabling it in the config file.

These methods help you narrow down issues without guesswork.

Final Thoughts

Debugging doesn’t have to be painful.

By combining structured tests, clean configuration, and the right tools, you can save hours during development and focus on building great tests instead of chasing errors.

Hope this helps you debug faster!

Written by Pranav Bharti