What Is Code Coverage and Why Is It Important?

Code coverage is a measure of how much code is executed or covered by tests. The primary purpose of code coverage analysis is to determine the effectiveness and completeness of a test suite in identifying and verifying defects in the given software.

Understanding code coverage

Code coverage is typically expressed as a percentage and provides the following insights:

• Line coverage: This metric measures the percentage of the executable lines of code executed during testing. A line is considered covered if it’s executed at least once during the testing process.

• Branch coverage: This metric, also known as decision coverage, assesses the percentage of decision points (if statements, loops) where both the true and false conditions are tested. It ensures that both sides of each decision point are exercised.

• Statement coverage: This is similar to line coverage but focuses on executable statements, so even if multiple statements are on a single line, they are treated as individual units. It’s a more fine-grained metric than line coverage.

• Method coverage: This metric measures the percentage of the codebase methods invoked or called by the test suite.

• Class/module/package coverage: These metrics assess the percentage of classes, modules, or packages used or instantiated during testing.