Tests are not only for checking correctness — they are also powerful tools for debugging.
When something breaks, a failing test tells you exactly where to look.
Instead of searching the entire codebase, you focus on the part that failed.
Using tests for debugging helps developers fix issues faster and with more confidence.
How Tests Help in Debugging
- Show exactly which function is failing
- Reproduce bugs easily
- Prevent the same bug from returning
- Make fixes safer
- Reduce guesswork
A good test acts like a safety net for your code.
The function is supposed to add tax once, but it adds tax twice.
This kind of logic error can easily go unnoticed without testing.
The test fails and clearly shows the expected and actual values.
This makes the bug easy to identify.
These examples show how tests guide developers directly to bugs.
By using tests as debugging tools, students gain the ability to fix problems quickly and safely — a professional skill used daily in real-world JavaScript development.