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Martin
Martin

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Code Coverage + Test Coverage

Comparison

Code Coverage Test Coverage
Question Did we execute the code? Did we test all features?
Type Quantitative (%) Qualitative (requirements)
Approach White-box (code-aware) Black-box (input/output focused)
Purpose Find untested code Verify requirements are met

Differences

Code Coverage measures how much of your source code runs during tests. It's a number: 80%, 90%, etc.

Test Coverage measures how well your tests cover actual features and user scenarios. It's about completeness of requirements, not lines of code.

Example

You can have 100% code coverage (every line executed) but still miss bugs. Why? Because you didn't test what users actually need to doβ€”like "user can log in" - which is low test coverage.

Conversely, good test coverage doesn't guarantee every code path was touched.

Bottom Line

Both metrics work together:

  • Code Coverage = safety net (did we run it?)
  • Test Coverage = quality net (does it work?)

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