As software products become more complex, testers seek innovative ways to detect bugs. But as they embrace new tools and methods, they must continue to follow some principles.

These principles seek to verify the specification, functionality, and performance of any software under test. They also ensure the software meets the intended business and customer requirements consistently and continuously. Let’s look at the seven principles of software testing:

1. Testing Shows the Presence of Defects

The first principle of software testing states that testing shows the presence of defects. So, what does this mean? The goal of software testing is to identify the presence of defects. However, no testing approach or methodology can ever prove that there are no defects in software.

While continuous testing can help identify weaknesses, it cannot remove them altogether. Even if no defects are found, testing cannot be considered a proof of correctness.

2. Exhaustive Testing Is Not Possible

Exhaustive testing aims to test software for all possible scenarios, paths, and input combinations. The second principle of software testing says that exhaustive testing is impossible. This is because testers cannot possibly cover all test scenarios from a time, cost, and effort perspective.

While they will try to cover as many scenarios as possible, some faults will continue to exist in the software under test. These faults must be ignored as long as they do not impact performance or functionality.

3. Early Testing

Another principle of software testing states that testing must start early in the software development lifecycle. Bugs or defects detected in the early lifecycle phases are less expensive to resolve.

Quicker resolution also helps influence the user experience, ensuring higher satisfaction and loyalty. So, it is advisable to begin the testing process the moment the testing requirements are defined.

4. Defect Clustering

Defect clustering states that in any software product, there are bound to be some modules that contain the maximum number of defects. It is believed that 80% of bugs are found in 20% of modules.

Understanding how, why, or where defect clustering happens is a great way to identify areas of the software that are largely susceptible to defects and flag modules with the biggest risks. Testers can prioritize efforts and focus on resolving the most critical defects first.

5. Pesticide Paradox

Running the same test cases again and again will not result in the detection of new bugs. Over time, they will stop being effective at catching bugs while causing a delay in delivering or deploying software.

Since it is practically impossible to test all possible scenarios, testers must constantly maintain and update their test case design. This is important because the functionality of any software application changes over time. That said, continuous maintenance aids in adapting testing approaches to new changes and discontinuing those that are no longer effective.

6. Testing is Context-Dependent

This principle of software testing asserts that the testing approach depends largely on the context of the software under development. Different types of software demand different testing techniques, tools, and approaches. For instance, testing an AI chatbot will be very different from testing a mobile gaming application.

7. Absence of Errors Fallacy

The last of the software testing principles states that developed software that is 99% bug-free can still be unstable. The absence of errors does not necessarily mean the software meets performance and functionality requirements.

Software testing is not merely finding defects but also checking that the software under test addresses business needs. Instead of trying to eliminate every error, testers should verify if the software follows user requirements.