Which is the best definition of complete testing?

The definition that states you have tested every statement, branch, and combination of branches in the program is the most comprehensive understanding of complete testing. This approach, known as thorough testing, ensures that all aspects of the code are evaluated for correctness. It focuses on achieving thorough coverage of the program's logic, which is crucial because it helps to uncover issues that may not be revealed through more superficial testing.

When every statement and branch is executed, as well as all combinations of branches, it significantly reduces the risk of undetected defects. This level of detail in testing is essential for high-quality software, particularly for complex systems where intricate interactions between different parts of the code can lead to subtle bugs.

While discovering every bug in the program is an admirable goal, it is inherently unachievable due to the vast number of possible inputs and states in complex software. Similarly, reaching a scheduled ship date does not guarantee that all functionalities have been examined thoroughly. Finally, merely completing every test in the test plan does not ensure that those tests were robust or comprehensive enough to verify all aspects of the software, as test plans can vary in design and thoroughness. Thus, focusing on complete statement and branch coverage ultimately provides the most reliable foundation for asserting that testing is complete.