test-gen

name	test-gen
description	Generate unit tests for selected code. Use when user says "add tests", "write unit tests", "generate test cases", or highlights code needing test coverage.

Unit Test Generator

Generate comprehensive unit tests for the selected code.

Workflow

1. Read the selected function/class
2. Identify: inputs, outputs, edge cases, dependencies
3. Generate tests in the appropriate framework
4. Cover: happy path, edge cases, error cases, boundary values

Framework by Language

Language	Framework
JavaScript	Jest / Vitest
TypeScript	Jest / Vitest
Python	pytest
Java	JUnit 5
Go	testing
Rust	#[test]
Ruby	RSpec

Coverage Checklist

For each function, generate tests for:

• ✅ Happy path — normal input → expected output
• ✅ Edge cases — empty, null, undefined, 0, -1
• ✅ Error cases — invalid input, exceptions
• ✅ Boundary values — max, min, off-by-one
• ✅ Async — promise resolve/reject (if applicable)

Output Format

// filename.test.ts
import { describe, it, expect } from 'vitest';

describe('functionName', () => {
  // Happy path
  it('should return expected result for normal input', () => {
    expect(functionName(input)).toBe(expected);
  });

  // Edge cases
  it('should handle empty input', () => {
    expect(functionName('')).toBe(expected);
  });

  // Error cases
  it('should throw for invalid input', () => {
    expect(() => functionName(invalid)).toThrow();
  });
});

Rules

• Use the project's existing test framework, don't introduce new ones
• Match existing test style (naming, structure, assertions)
• Mock external dependencies (API calls, DB, file system)
• Tests should be runnable immediately — don't reference undefined fixtures