Tests Cannot Prevent Every Bug
Understand the reasons why testing cannot detect every bug and the inherent limitations in test coverage within test-driven development. Learn how disciplined test creation reduces defects and why integrating TDD improves software quality despite some undetected issues. Discover when to balance testing efforts to maximize quality and efficiency during development.
A very old objection to testing of any kind is:
"We cannot catch every bug."
While this is certainly true, if anything, it means that we need more and better testing, not less. Let’s understand the motivations behind this one to prepare an appropriate response.
Understanding why people say tests cannot catch every bug
Straight away, we can agree with this statement. Tests cannot catch every bug. More precisely, it has been proven that testing in software systems can only reveal the presence of defects. It can never prove that no defects exist. We can have many passing tests, and defects can still hide in the places we haven’t tested.
This seems to apply in other fields as well. Medical scans will not always reveal problems that are too faint to notice. Wind tunnel tests for ...