Automatically suggest tests for new functions and components. Use when new code is written, functions added, or user mentions testing. Creates test scaffolding with Jest, Vitest, Pytest patterns. Triggers on new functions, components, test requests, testing mentions.
Comprehensive test suites → Use @test-engineer sub-agent
Integration tests → Use @test-engineer sub-agent
E2E test design → Use @test-engineer sub-agent
Test strategy planning → Use @test-engineer sub-agent
Relationship with @test-engineer Sub-Agent
Me (Skill): Quick test scaffolding
@test-engineer (Sub-Agent): Comprehensive testing strategy
Workflow
You write a function
I auto-generate basic test structure
You want full suite → Invoke @test-engineer sub-agent
Sub-agent creates comprehensive tests
Examples
JavaScript Function
// You write:
function calculateDiscount(price, percentage) {
if (price <= 0) throw new Error('Invalid price');
return price * (percentage / 100);
}
// I auto-generate:
describe('calculateDiscount', () => {
it('calculates discount correctly', () => {
expect(calculateDiscount(100, 10)).toBe(10);
});
it('throws error for invalid price', () => {
expect(() => calculateDiscount(0, 10)).toThrow('Invalid price');
});
it('handles zero percentage', () => {
expect(calculateDiscount(100, 0)).toBe(0);
});
// TODO: Add more edge cases
// Consider: negative percentages, decimal values, very large numbers
});
React Component
// You write:
function UserCard({ user, onEdit }) {
return (
<div className="user-card">
<h2>{user.name}</h2>
<button onClick={() => onEdit(user.id)}>Edit</button>
</div>
);
}
// I auto-generate:
import { render, screen, fireEvent } from '@testing-library/react';
describe('UserCard', () => {
const mockUser = { id: 1, name: 'John Doe' };
const mockOnEdit = jest.fn();
it('renders user name', () => {
render(<UserCard user={mockUser} onEdit={mockOnEdit} />);
expect(screen.getByText('John Doe')).toBeInTheDocument();
});
it('calls onEdit with user id when button clicked', () => {
render(<UserCard user={mockUser} onEdit={mockOnEdit} />);
fireEvent.click(screen.getByText('Edit'));
expect(mockOnEdit).toHaveBeenCalledWith(1);
});
// TODO: Add tests for edge cases
// - Missing user data
// - Undefined onEdit
// - Long names (UI testing)
});
Python Function
# You write:
def fetch_user_data(user_id: int) -> dict:
if user_id <= 0:
raise ValueError("Invalid user ID")
return db.query("SELECT * FROM users WHERE id = ?", [user_id])
# I auto-generate:
import pytest
def test_fetch_user_data_success():
"""Test successful user data retrieval"""
result = fetch_user_data(1)
assert isinstance(result, dict)
assert 'id' in result
def test_fetch_user_data_invalid_id():
"""Test with invalid user ID"""
with pytest.raises(ValueError, match="Invalid user ID"):
fetch_user_data(0)
def test_fetch_user_data_negative_id():
"""Test with negative ID"""
with pytest.raises(ValueError):
fetch_user_data(-1)
# TODO: Add integration tests with database
# TODO: Test database connection failures
Me: "Generated 3 basic tests for calculateDiscount()"
You: "@test-engineer create comprehensive test suite with all edge cases"
Sub-agent: [Creates 25+ tests covering all scenarios]
Sandboxing Compatibility
Works without sandboxing: ✅ Yes
Works with sandboxing: ✅ Yes
