Code coverage

In computer science, code coverage is a measure used to describe the degree to which the source code of a program is tested by a particular test suite. A program with high code coverage has been more thoroughly tested and has a lower chance of containing software bugs than a program with low code coverage. Many different metrics can be used to calculate code coverage; some of the most basic are the percent of program subroutines and the percent of program statements called during execution of the test suite.

Code coverage was among the first methods invented for systematic software testing. The first published reference was by Miller and Maloney in Communications of the ACM in 1963.

Coverage criteria

To measure what percentage of code has been exercised by a test suite, one or more coverage criteria are used. Coverage criteria is usually defined as a rule or requirement, which test suite needs to satisfy.

Basic coverage criteria

There are a number of coverage criteria, the main ones being: