Tool Mentor: Code Coverage Tool

Code coverage tools yield information on which parts of the program code were used during a test. As such they provide practical support to measure the effect of the test design techniques used. The measurements are made at the program or subsystem level. In this way, it is established whether each program statement is executed at least once during testing. The conclusions drawn must be investigated because:

100% coverage of the program statements does not guarantee by any means that no defects remain! Compare section Essential Test Design Concepts.
A test designed to achieve 100% coverage of the functional specifications does not generally automatically achieve 100% statement coverage.