juniorUnit Testing
What is test coverage?
Updated May 6, 2026
Short answer
Test coverage measures how much code is executed by tests.
Deep explanation
Coverage includes line, branch, and function coverage. High coverage increases confidence but doesn't guarantee bug-free code.
Real-world example
Ensuring critical payment logic is fully tested.
Common mistakes
- Chasing 100% coverage without meaningful tests.
Follow-up questions
- What types of coverage exist?
- Is 100% coverage necessary?