Explain the concept of code coverage in software testing.

Code coverage is a metric used in software testing to measure the extent to which the source code of a program has been executed during testing. It helps in determining the effectiveness of the testing process by identifying areas of the code that have not been tested.

Code coverage is typically measured as a percentage and can be categorized into different levels such as statement coverage, branch coverage, and path coverage.

Statement coverage measures the percentage of statements in the code that have been executed during testing. It ensures that each line of code has been executed at least once.

Branch coverage, on the other hand, measures the percentage of branches or decision points in the code that have been executed. It ensures that both true and false branches of conditional statements have been tested.

Path coverage is the most comprehensive level of code coverage and measures the percentage of all possible paths through the code that have been executed. It ensures that all possible combinations of conditions and loops have been tested.

Code coverage helps in identifying areas of the code that are not being tested, which can be potential sources of bugs or defects. It also helps in assessing the thoroughness of the testing process and provides insights into the overall quality of the software.

However, it is important to note that achieving 100% code coverage does not guarantee the absence of bugs or defects. It only indicates that all lines of code have been executed, but it does not guarantee that all possible scenarios and edge cases have been tested. Therefore, code coverage should be used in conjunction with other testing techniques and strategies to ensure comprehensive testing and quality assurance.