Test Writer

Overview

Analyzes source code and auto-generates comprehensive unit and integration tests.

When to Use

• User asks to "write tests" or "add test coverage"
• User wants to "test this function"

How It Works

Step 1: Detect test framework

Check: package.json (jest/mocha), pytest.ini, pyproject.toml, conftest.py

Step 2: Parse source

Read source files. Identify: function signatures, parameters, return types, error handling, edge cases.

Step 3: Generate test cases

For each function generate: happy path, edge cases (empty/null/zero), error cases, boundary cases.

Step 4: Write test file

JavaScript: __tests__/filename.test.js or filename.test.js

Python: tests/test_filename.py

Templates

Jest

describe('functionName', () => {

test('should return expected result', () => {

expect(functionName(input)).toBe(expected);

});

test('should throw for invalid input', () => {

expect(() => functionName(invalid)).toThrow();

});

});

Pytest

def test_function_normal():

assert function_name(input) == expected

def test_function_invalid():

with pytest.raises(ErrorType):

function_name(invalid)

Tips

• Target 80%+ coverage on critical functions
• Cover all branches and error paths
• Mock external dependencies (API, filesystem, DB)