Create Tests

Generate comprehensive test cases for code.

Overview

Use this skill to draft focused tests that cover behavior, edge cases, and failures without coupling the tests to implementation details.

When to Use

• Writing new unit tests
• Adding integration or acceptance coverage
• Reproducing a bug with a failing test first
• Checking whether a change has enough verification

Quick Start

1. Identify the behavior or acceptance criterion
2. Add one happy-path test
3. Add the most important edge case
4. Add the failure mode or invalid input case
5. Run the narrowest possible test command first

Test Categories

Python (pytest)

import pytest

class TestFunction:
    def test_valid_input_returns_expected(self):
        assert function("valid") == "expected"
    
    def test_empty_input_returns_empty(self):
        assert function("") == ""
    
    def test_invalid_raises_error(self):
        with pytest.raises(ValueError):
            function(None)

JavaScript (Jest)

describe('function', () => {
  it('returns expected for valid input', () => {
    expect(fn('valid')).toBe('expected');
  });

  it('handles empty input', () => {
    expect(fn('')).toBe('');
  });

  it('throws for invalid', () => {
    expect(() => fn(null)).toThrow();
  });
});

Naming Convention

test_[what]_[condition]_[expected]

test_login_valid_credentials_returns_token
test_login_wrong_password_raises_error

Coverage Goals

Best Practices

• Test behavior, not implementation
• One assertion per test
• Mock external dependencies
• Keep tests fast

Core Workflow

Follow the primary workflow, commands, and decision points documented in the sections below.

Examples

Use the examples and snippets already present in this document whenever they apply to the task.

References

Use any linked scripts, assets, reference files, and companion resources mentioned in this document.