test-gen

When to use

• Generating unit tests for a specific function or file (happy path, edge cases, error handling).
• Writing tests first (TDD) before implementing new functionality.
• Use /test-gen for per-function unit tests; use /test-matrix for project-wide testing strategy.

Complements /test-matrix. /test-gen owns per-function unit tests (happy / edge / error). /test-matrix owns project-wide testing strategy (fuzz / property / load / e2e / mutation) and CI wiring. Use /test-gen for a specific function, /test-matrix at project kickoff or when coverage gaps span paradigms. See skills/test-matrix/SKILL.md.

Test Generation Workflow

Step 1: Analyze Target

• Read the target file/function completely
• Identify: inputs, outputs, side effects, dependencies, error paths
• Check existing test files — don't duplicate

Step 2: Detect Framework

• Auto-detect test framework from project:
  • Python: pytest (conftest.py, pytest.ini) or unittest
  • JS/TS: jest (jest.config), vitest (vitest.config), mocha
  • Flutter: flutter_test
  • Go: built-in testing
• Match existing test file naming: test_*.py, *.test.ts, *_test.dart, *_test.go

Step 3: Plan Test Cases

Categories (in order of priority):

1. Happy path — normal expected usage (2-3 cases)
2. Edge cases — boundaries, empty inputs, max values (2-3 cases)
3. Error handling — invalid inputs, missing data, network errors (1-2 cases)
4. Integration — only if function interacts with external services (1 case with mock)

Step 4: Write Tests

• Follow existing test patterns in the project
• Use descriptive test names: test_<function>_<scenario>_<expected>
• One assertion per test (prefer)
• Mock external dependencies, not internal logic
• Use fixtures/factories from existing test infrastructure

Step 5: Run & Verify

• Run new tests — all must pass
• Run full test suite — no regressions
• Check coverage delta if coverage tool available

Step 6: Commit

• test: add tests for <target>