---name: rubydescription: Ruby development guidelines covering idiomatic code style, Ruby 3.x features, testing with RSpec, and best practices for building maintainable Ruby applications.---

Ruby Development

You are an expert in Ruby development, including Ruby 3.x features, testing frameworks, and modern Ruby best practices.

Code Style and Structure

• Write concise, idiomatic Ruby code with accurate examples
• Adhere to Ruby community conventions and style guides
• Use snake_case for files, methods, and variables
• Use CamelCase for classes and modules
• Favor descriptive names like user_signed_in? and calculate_total

Ruby Language Features

• Leverage Ruby 3.x capabilities including:
  • Pattern matching with case/in
  • Endless methods for simple one-liners
  • Keyword arguments for clarity
  • Safe navigation operator (&.)
• Use blocks, procs, and lambdas effectively
• Apply metaprogramming judiciously

Syntax and Formatting

• Follow the Ruby Style Guide
• Employ expressive syntax features
• Prefer single quotes except when string interpolation is needed
• Use meaningful method and variable names
• Keep methods small and focused (Single Responsibility Principle)

Error Handling

• Apply exceptions for genuine edge cases only
• Implement proper logging with user-friendly messages
• Use custom exception classes for domain-specific errors
• Handle errors gracefully with appropriate rescue blocks

Object-Oriented Design

• Follow SOLID principles
• Favor composition over inheritance
• Use modules for shared behavior (mixins)
• Keep classes focused and cohesive

Testing Best Practices

RSpec Guidelines

• Write comprehensive coverage of typical cases, edge cases, and error conditions
• Use clear, descriptive naming conventions for test blocks
• Organize logically with describe for classes/methods and context for scenarios
• Use let and factories (FactoryBot) instead of fixtures
• Ensure test independence with minimal shared state
• Mock external services strategically while testing real behavior when possible

Test Structure

describe ClassName do
  describe '#method_name' do
    context 'when condition exists' do
      it 'does expected behavior' do
        expect(result).to eq(expected)
      end
    end
  end
end

Performance Optimization

• Profile code before optimizing
• Use appropriate data structures
• Leverage lazy enumerators for large collections
• Cache expensive computations

Security

• Sanitize user input
• Use parameterized queries
• Keep dependencies updated
• Follow security best practices for handling sensitive data