The metric of 100% code coverage has become a frequently used buzzword in the software development world, suggesting excellent testing quality. However, it's worth remembering that achieving full code coverage does not guarantee that all possible test cases have been considered. Focusing solely on the 100% code coverage metric can lead to overly complicated tests or the creation of tests that don't actually verify important aspects of the code. It's important to use code coverage as one of many quality indicators for tests while also focusing on finding and eliminating real weaknesses in the testing process and ensuring a thorough verification of the application's logic and functionality.

Yet some additional techniques like Static Code Analysis are working great next to high code coverage. Mutation testing is a type of software testing that involves deliberately introducing errors (so-called mutations) into the program's code to assess the quality of unit tests. In mutation testing, the program undergoes a series of mutations, and tests are then run to check whether the tests detect these changes. Fuzz testing, also known as fuzzing, is a software testing technique that involves inputting random, distorted, or invalid data into a program to detect errors or security vulnerabilities. Fuzz testing allows for the automated generation of a massive number of tests, which can help in uncovering hard-to-detect bugs in software.