Agent skill
localsetup-test-runner
Write and run tests across languages and frameworks (Vitest, Jest, pytest, XCTest, Playwright). TDD workflow, coverage, and test patterns.
Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/other/other/localsetup-test-runner
Metadata
Additional technical details for this skill
- version
- 1.1
SKILL.md
test-runner
Write and run tests across languages and frameworks.
Framework Selection
| Language | Unit Tests | Integration | E2E |
|---|---|---|---|
| TypeScript/JS | Vitest (preferred), Jest | Supertest | Playwright |
| Python | pytest | pytest + httpx | Playwright |
| Swift | XCTest | XCTest | XCUITest |
Quick Start by Framework
Vitest (TypeScript / JavaScript)
npm install -D vitest @testing-library/react @testing-library/jest-dom
// vitest.config.ts
import { defineConfig } from 'vitest/config'
export default defineConfig({
test: {
globals: true,
environment: 'jsdom',
setupFiles: './tests/setup.ts',
},
})
npx vitest # Watch mode
npx vitest run # Single run
npx vitest --coverage # With coverage
Jest
npm install -D jest @types/jest ts-jest
npx jest # Run all
npx jest --watch # Watch mode
npx jest --coverage # With coverage
npx jest path/to/test # Single file
pytest (Python)
uv pip install pytest pytest-cov pytest-asyncio httpx
pytest # Run all
pytest -v # Verbose
pytest -x # Stop on first failure
pytest --cov=app # With coverage
pytest tests/test_api.py -k "test_login" # Specific test
pytest --tb=short # Short tracebacks
XCTest (Swift)
swift test # Run all tests
swift test --filter MyTests # Specific test suite
swift test --parallel # Parallel execution
Playwright (E2E)
npm install -D @playwright/test
npx playwright install
npx playwright test # Run all
npx playwright test --headed # With browser visible
npx playwright test --debug # Debug mode
npx playwright test --project=chromium # Specific browser
npx playwright show-report # View HTML report
TDD Workflow
- Red — Write a failing test that describes the desired behavior.
- Green — Write the minimum code to make the test pass.
- Refactor — Clean up the code while keeping tests green.
┌─────────┐ ┌─────────┐ ┌──────────┐
│ Write │────▶│ Write │────▶│ Refactor │──┐
│ Test │ │ Code │ │ Code │ │
│ (Red) │ │ (Green) │ │ │ │
└─────────┘ └─────────┘ └──────────┘ │
▲ │
└──────────────────────────────────────────┘
Test Patterns
Arrange-Act-Assert
test('calculates total with tax', () => {
// Arrange
const cart = new Cart([{ price: 100, qty: 2 }]);
// Act
const total = cart.totalWithTax(0.08);
// Assert
expect(total).toBe(216);
});
Testing Async Code
test('fetches user data', async () => {
const user = await getUser('123');
expect(user.name).toBe('Colt');
});
Mocking
import { vi } from 'vitest';
const mockFetch = vi.fn().mockResolvedValue({
json: () => Promise.resolve({ id: 1, name: 'Test' }),
});
vi.stubGlobal('fetch', mockFetch);
Testing API Endpoints (Python)
import pytest
from httpx import AsyncClient
from app.main import app
@pytest.mark.asyncio
async def test_get_users():
async with AsyncClient(app=app, base_url="http://test") as client:
response = await client.get("/users")
assert response.status_code == 200
assert isinstance(response.json(), list)
Testing React Components
import { render, screen, fireEvent } from '@testing-library/react';
import { Button } from './Button';
test('calls onClick when clicked', () => {
const handleClick = vi.fn();
render(<Button onClick={handleClick}>Click me</Button>);
fireEvent.click(screen.getByText('Click me'));
expect(handleClick).toHaveBeenCalledOnce();
});
Coverage Commands
# JavaScript/TypeScript
npx vitest --coverage # Vitest (uses v8 or istanbul)
npx jest --coverage # Jest
# Python
pytest --cov=app --cov-report=html # HTML report
pytest --cov=app --cov-report=term # Terminal output
pytest --cov=app --cov-fail-under=80 # Fail if < 80%
# View HTML coverage report
open coverage/index.html # macOS
open htmlcov/index.html # Python
What to Test
Always test:
- Public API / exported functions
- Edge cases: empty input, null, boundary values
- Error handling: invalid input, network failures
- Business logic: calculations, state transitions
Don't bother testing:
- Private implementation details
- Framework internals (React rendering, Express routing)
- Trivial getters/setters
- Third-party library behavior
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