generate_unit_tests – Professional Test Suite Creation

Comprehensive test generation with framework-specific patterns and intelligent coverage analysis

Perfect For

Legacy Code Safety
Add comprehensive test coverage to inherited codebases before refactoring, ensuring changes don’t break existing functionality.

Test-Driven Development
Generate test scaffolding alongside implementation, maintaining development velocity whilst ensuring quality standards.

API Endpoint Testing
Complete endpoint testing with various request/response scenarios, authentication flows, and error condition handling.

Component Behaviour Verification
React, Vue, and Angular component testing with user interaction simulation and state management validation.

Critical Path Coverage
Ensure business-critical functions have comprehensive test coverage with edge case scenarios and error handling validation.

Quick Start

local-llm:generate_unit_tests with:
- filePath: "C:/src/UserService.ts"
- testFramework: "jest"
- coverageTarget: "comprehensive"

React component testing:

local-llm:generate_unit_tests with:
- filePath: "C:/components/LoginForm.tsx"
- testFramework: "jest"
- context: {"framework": "React", "testingLibrary": true}
- coverageTarget: "comprehensive"

Test Generation Output

Complete Test Suites

• Framework-Specific Structure: Jest describe/it blocks, Mocha test organization, or pytest fixtures
• Setup and Teardown: beforeEach/afterEach patterns with proper resource cleanup
• Mock Implementations: Sophisticated mocking for databases, APIs, and external dependencies

Comprehensive Coverage

• Function Coverage: Tests for every public method with parameter validation
• Branch Coverage: All conditional paths tested including error conditions
• Edge Case Testing: Boundary conditions, null/undefined handling, and invalid input scenarios
• Integration Scenarios: Cross-module communication and dependency interaction testing

Advanced Testing Patterns

• Async Testing: Promise handling, async/await patterns, and timeout scenarios
• Error Condition Testing: Exception handling, network failures, and recovery mechanisms
• Performance Testing: Critical path performance validation and resource usage monitoring

Test Generation Example

Source Code

export class UserService {
  constructor(private db: Database) {}

  async createUser(userData: UserData): Promise {
    if (!userData.email || !userData.name) {
      throw new Error('Email and name are required');
    }
    
    const existingUser = await this.db.findByEmail(userData.email);
    if (existingUser) {
      throw new Error('User already exists');
    }
    
    return await this.db.create(userData);
  }
}

Generated Test Suite

describe('UserService', () => {
  let userService: UserService;
  let mockDb: jest.Mocked;

  beforeEach(() => {
    mockDb = {
      findByEmail: jest.fn(),
      create: jest.fn(),
    } as jest.Mocked;
    userService = new UserService(mockDb);
  });

  describe('createUser', () => {
    it('should create user with valid data', async () => {
      const userData = { email: 'test@example.com', name: 'John Doe' };
      const expectedUser = { id: 1, ...userData };
      
      mockDb.findByEmail.mockResolvedValue(null);
      mockDb.create.mockResolvedValue(expectedUser);
      
      const result = await userService.createUser(userData);
      
      expect(result).toEqual(expectedUser);
      expect(mockDb.findByEmail).toHaveBeenCalledWith(userData.email);
    });

    it('should throw error for missing email', async () => {
      const userData = { name: 'John Doe' } as UserData;
      
      await expect(userService.createUser(userData))
        .rejects.toThrow('Email and name are required');
    });

    it('should throw error for existing user', async () => {
      const userData = { email: 'existing@example.com', name: 'Jane' };
      mockDb.findByEmail.mockResolvedValue({ id: 1 } as User);
      
      await expect(userService.createUser(userData))
        .rejects.toThrow('User already exists');
    });
  });
});

Parameters

Framework Support

• Jest (JavaScript/TypeScript): Complete ecosystem with mocking, snapshots, and coverage reporting
• Mocha + Chai: Flexible test structure with expressive assertions and custom matchers
• PyTest (Python): Fixture-based testing with parametrised tests and advanced assertion introspection
• PHPUnit (PHP): WordPress and Laravel compatible testing with data providers and mock objects

Advanced Configuration

Framework-Specific Testing: Tailored test generation for different technology stacks with appropriate testing patterns and library integration.

// React Testing Library integration
local-llm:generate_unit_tests with:
- filePath: "C:/components/UserProfile.tsx"
- testFramework: "jest"
- context: {
    "framework": "React",
    "testingLibrary": true,
    "userEvents": true
  }

// Node.js API testing with supertest
local-llm:generate_unit_tests with:
- filePath: "C:/routes/users.js"
- testFramework: "jest"
- context: {
    "framework": "Express",
    "database": "MongoDB",
    "supertest": true
  }

// WordPress plugin testing
local-llm:generate_unit_tests with:
- filePath: "C:/wp-plugin/includes/class-user-manager.php"
- testFramework: "phpunit"
- context: {
    "framework": "WordPress",
    "version": "6.4"
  }

Testing Workflow Integration:

1. Run analyze_single_file to understand code structure
2. Generate comprehensive test suite with generate_unit_tests
3. Implement refactoring improvements with confidence
4. Document testing strategy with generate_documentation

Testing Best Practices

Test Structure: Generated tests follow AAA pattern (Arrange, Act, Assert) with clear test descriptions and meaningful assertions.

Mock Strategy: Intelligent mocking of external dependencies whilst preserving unit under test isolation and realistic behaviour simulation.

Edge Case Coverage: Comprehensive boundary testing including null values, empty collections, network timeouts, and resource constraints.

Performance Considerations: Tests include performance assertions for critical paths and resource usage validation where appropriate.

Pro Tips

Incremental Testing: Start with basic coverage for critical functions, then expand to comprehensive testing for complete system validation.

Test Maintenance: Generated tests serve as living documentation – update them alongside code changes to maintain accuracy.

CI/CD Integration: Use generated tests as foundation for automated testing pipelines and quality gates.

Related Functions

• analyze_single_file – Understand code structure before test generation
• suggest_refactoring – Identify code improvements that enhance testability
• generate_documentation – Document testing strategy and coverage expectations
• security_audit – Ensure tests cover security-critical code paths