Code coverage tools measure how thoroughly tests exercise programs. There are many different coverage measures, including statement coverage, branch coverage, and multiple-condition coverage. The coverage tool would modify the code to record the statements executed and which expressions evaluate which way (the true case or the false case of the expression).
Modification is done either to the source code or to the executable the compiler generates. There are several commercial and freeware coverage tools available. Coverage tool selection should be based on the type of coverage measure selected, the language of the source code, the size of the program, and the ease of integration into the build process.
