Legacy Code Rescue

"Legacy code is code without tests." — Michael Feathers

Rescue Strategies

1. Sprout Method / Class

• When you need to add functionality, write it as new, tested code (a "sprout") and call it from the legacy code.
• Benefit: Ensures new code is tested immediately.

2. Wrap Method / Class

• Wrap an existing method or class with a new one that contains the new logic and calls the original.
• Benefit: Provides a clear boundary for testing new behavior.

3. Breaking Dependencies

• Identify "Seams" (places where you can change behavior without editing code in that place).
• Use Dependency Injection or Subclass & Override to isolate the logic you want to test.