tdd-refactor-phase

To safely refactor code without breaking existing behavior, use a test-driven development workflow where behavior-testing principles guide incremental structural improvements after all tests pass. This ensures changes reduce duplication or decouple components while maintaining observable functionality.

In a TDD workflow, refactoring should start immediately after tests pass. Once the behavior is verified by green tests, you can safely clean up duplicated code, extract logic into services, or improve the organization of large files incrementally.

The best way to reduce code duplication after writing new features is to refactor the code structurally while relying on behavior-driven tests as a safety net. This incremental approach decouples components and improves maintainability without altering observable software behavior.

Yes, you can decouple components in a large file without changing software behavior by following a structured refactoring process guided by passing behavior tests. This ensures the internal design improves while the external observable functionality remains identical.

Yes, refactoring requires all tests to be green first to ensure a reliable safety net. Passing behavior-driven tests verify that the current observable behavior is correct before you begin incrementally improving the internal code structure and design.

Code maintainability degrades if you skip the refactoring phase because duplicated logic and tightly coupled components accumulate. Without a structured, test-driven approach to improving design after features are added, the codebase becomes increasingly difficult to manage and extend.