Reading list: Is test driven development useful for legacy code refactoring?
Yes, test driven development is highly useful for legacy code refactoring, and it is widely considered one of the safest and most effective approaches for improving existing software systems.

Legacy code often lacks proper documentation and automated tests, making changes risky. By applying test driven development, developers begin by writing tests that describe the current behavior of the system. These tests act as a safety net, ensuring that refactoring does not break existing functionality while the internal structure of the code is improved.

One of the biggest advantages of using test driven development for legacy code is risk reduction. Before modifying complex or tightly coupled code, tests created through test driven development validate expected outputs. This allows teams to confidently clean up code, remove duplication, and improve readability without fear of introducing regressions.

Additionally, test driven development helps teams gradually modernize legacy applications. Instead of rewriting the entire system, developers can refactor small components step by step, supported by tests. This incremental approach reduces downtime, improves maintainability, and makes legacy systems easier to scale and extend.

In summary, test driven development is a practical and proven method for legacy code refactoring. It improves code stability, enables safer changes, and transforms fragile legacy systems into reliable and maintainable software over time.
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