Unit Testing Skill

Purpose

This skill provides unit testing conventions for isolated tests of pure functions, Zod validation schemas, and utility modules. Unit tests run without database or external service dependencies.

Activation

This skill activates when:

• Creating or modifying files in tests/unit/
• Testing Zod validation schemas
• Testing pure utility functions
• Testing data transformers or formatters

File Patterns

• tests/unit/**/*.test.ts

Workflow

1. Detect unit test work (file path contains tests/unit/)
2. Load references/Unit-Testing-Conventions.md
3. Also load testing-base skill for shared conventions
4. Apply unit test patterns with proper isolation
5. Validate no database or external service dependencies

Key Patterns (REQUIRED)

Test Structure

• Use describe/it blocks (no imports - globals enabled)
• Follow Arrange-Act-Assert pattern
• Test pure functions in isolation
• Mock ALL external dependencies with vi.mock()

Validation Schema Testing

• Test valid input scenarios
• Test invalid input scenarios with specific error expectations
• Test edge cases (empty strings, null, undefined, boundary values)
• Use safeParse for validation testing

Isolation Requirements

• NO database access in unit tests
• NO MSW handlers needed (no API calls)
• Mock external imports with vi.mock()
• Tests should run without any external services

References

• references/Unit-Testing-Conventions.md - Complete unit testing conventions