CDK Testing Rules

General

• Follow a test-driven development approach.
• Keep tests simple and focused on one aspect of behavior
• Use Jest as the testing framework
• Use the AWS CDK assertions module for testing CDK constructs
• Use the Arrange-Act-Assert pattern
• Organize tests by construct or stack
• Use descriptive test names that explain the expected behavior
• Aim for high test coverage (at least 80%)
• Focus on testing critical infrastructure components
• Ensure all resource properties are tested

Unit Tests

• Use fine-grained assertions to test specific aspects of resources
• Use hasResourceProperties for partial matching and exactlyMatchTemplate for exact matching
• Use snapshot testing to detect unintended changes in CloudFormation templates
• Update snapshots only when changes are intentional
• Don’t rely solely on snapshots; combine with fine-grained assertions

Integration Tests

• Use the integ-tests-alpha module for integration testing
• Create separate integration test files with the .integ.ts suffix
• Define integration tests as CDK applications
• Test that resources are created successfully
• Test interactions between resources
• Clean up resources after tests complete