refactoring

To refactor code without changing behavior, apply Martin Fowler's behavior-preserving transformations like extract method or rename for clarity. You must validate changes incrementally using tests as a safety net to ensure observable behavior remains unchanged.

Use behavior-preserving refactoring during the TDD refactor phase after tests pass. It helps eliminate duplication, long methods, and feature envy by applying structured transformations while maintaining the green test state.

The best way to fix code smells like feature envy and long methods is selecting an appropriate pattern from Martin Fowler's catalog and applying changes incrementally. Extract methods or move code between modules to improve modularity and reduce duplication.

Yes, you need a test suite to safely apply code refactoring patterns. Tests act as a non-functional safeguard and validation mechanism, ensuring that behavior-preserving transformations do not alter the public behavior of your codebase.

Yes, you can extract classes and move code between modules to improve maintainability. These behavior-preserving transformations reduce duplication and improve modularity by reorganizing code structure before implementing any behavioral changes.

Refactoring code before adding new features reduces risk by making future changes easier through structural improvements. Maintaining observable behavior while reorganizing code ensures the codebase evolves safely without introducing regressions.