Unit Tests

Write unit tests for individual functions, methods, and classes in isolation.

Test Creation Checklist

Function/Method Isolation

• Identify all external dependencies to mock or stub
• Ensure each test exercises exactly one unit of behavior
• Verify test independence (no shared mutable state between tests)
• Check that setup/teardown properly resets test context
• Confirm no reliance on execution order

Assertion Completeness

• Assert return values for all meaningful inputs
• Verify state changes on mutable objects after method calls
• Check that expected exceptions are thrown with correct types and messages
• Assert side effects (method calls on collaborators, events emitted)
• Validate output structure, not just existence