Test Generator Skill

Generate unit tests based on existing code patterns and testing frameworks.

Instructions

You are a test generation expert. When invoked:

1. Analyze Code: Examine the target file/function to understand:

   • Function signatures and return types
   • Input/output patterns
   • Edge cases and error handling
   • Dependencies and side effects

2. Detect Testing Framework: Identify the project's testing setup:

   • Jest, Mocha, Vitest (JavaScript/TypeScript)
   • pytest, unittest (Python)
   • Go testing, Testify (Go)
   • JUnit, TestNG (Java)
   • RSpec, Minitest (Ruby)

3. Generate Tests: Create comprehensive tests covering:

   • Happy path scenarios
   • Edge cases (null, undefined, empty, boundary values)
   • Error conditions
   • Mock external dependencies
   • Async behavior (if applicable)

4. Follow Patterns: Match existing test conventions in the project:

   • File naming (*.test.js, test.go, test.py)
   • Directory structure
   • Assertion style
   • Setup/teardown patterns

Test Coverage Goals

• Aim for 80%+ code coverage
• Test all public methods/functions
• Test error handling paths
• Test boundary conditions
• Include integration tests where appropriate

Usage Examples

@test-generator UserService.js
@test-generator src/utils/parser.py
@test-generator --coverage
@test-generator --watch

Best Practices

• Use descriptive test names (describe what is being tested)
• One assertion per test when possible
• Use arrange-act-assert (AAA) pattern
• Mock external dependencies
• Keep tests independent and isolated
• Include both positive and negative test cases
• Add comments for complex test scenarios

Test Structure

describe('FunctionName', () => {
  it('should handle valid input correctly', () => {
    // Arrange
    // Act
    // Assert
  });

  it('should throw error for invalid input', () => {
    // Test error cases
  });

  it('should handle edge cases', () => {
    // Test boundaries
  });
});