characterization-test-red

Characterization tests capture the current observed behavior of legacy modules lacking unit tests, creating a regression safety net before you refactor. They document existing API boundaries and edge cases without modifying production code.

To safely refactor legacy code, first capture its current behavior with characterization tests across multiple edge cases. This generates a minimal baseline test suite that supports safe, behavior-preserving changes and prevents regressions.

You need characterization tests when refactoring legacy modules lacking existing test coverage. They are used to document and capture the actual observed behavior rather than testing intended design, ensuring regression safety during incremental changes.

Yes, this approach captures observed behavior across multiple edge cases in untested legacy modules. It guides you in creating minimal but comprehensive tests that document these boundaries, providing a baseline suite for future green-refactor work.

No, running characterization tests strictly avoids production changes during the behavior capture process. The goal is to generate a baseline test suite that documents existing functionality, ensuring the legacy module remains untouched before the actual refactor begins.