Testing checklist

Every rule in the testing playbook, by chapter, required rules first. Each links to its own page with how we built it and how to check it.

Test strategy

• Required Test what would hurt to break
• Required Shape the test suite like a pyramid
• Required Ship tests in the same change

Unit tests

• Required Test behaviour through the public interface
• Required Fake the clock and the network in unit tests
• Required Test the edges and the errors
• Recommended Arrange, act and assert
• Recommended Give each test one reason to fail
• Recommended Keep unit tests fast

Integration and contract tests

• Required Test against the same database engine
• Required Check the contract between services
• Recommended Fake only what you do not own
• Optional Check that outside services still match your fakes

End-to-end and browser tests

• Required Cover only the critical journeys
• Required Find elements the way people do
• Required Wait for the page to be ready instead of sleeping
• Required Run browser tests against the production build
• Recommended Test in more than one browser and size
• Recommended Smoke test every deploy

Test data and environments

• Required Give each test its own data
• Required Keep a staging copy with fake data
• Recommended Build test data with factories

Flaky and slow tests

• Required Quarantine flaky tests with an owner
• Recommended Find hidden order dependencies
• Recommended Find flaky tests before they merge
• Recommended Keep the suite within a time budget

Test quality

• Required Make every test able to fail
• Recommended Prove the tests catch bugs
• Recommended Treat coverage as a floor
• Recommended Review tests like code
• Recommended Keep snapshot tests small and reviewed

Non-functional tests

• Required Check accessibility in every build
• Required Grade AI features against fixed examples
• Recommended Test load against a budget
• Recommended Fuzz every parser of untrusted input