What aspect might code coverage fail to capture regarding test effectiveness?

Code coverage is a metric used to measure the proportion of code that is executed when tests are run. While it provides important insights, it does not fully capture the effectiveness of your tests in terms of the functionality they are intended to verify.

When considering functional testing, you are focused on whether the application behaves as expected in real-world scenarios and meets user requirements. Code coverage metrics may highlight that certain lines of code were executed during tests, but they do not assess whether the tests actually validate the functionality correctly or if they consider the various edge cases and user interactions.

Effective functional testing goes beyond just executing code; it includes ensuring that all user stories and requirements are covered and that the application functions as intended under different conditions. Therefore, while code coverage is useful, it is insufficient for completely assessing the thoroughness of functional testing, leading to potentially undetected defects or issues in the application.