Seven Principles of Software Testing

These Software Testing principles are not the only guiding truths for all testers to follow, but they will serve as a foundation for people looking to improve their testing skills. I find these principles universal and timeless. They apply to testers in all domains, for people working on any project and using any testing methodology.

Principles of Software Testing

These principles can be considered guiding rules to help you become a better tester. However, it is important to understand that each principle contains many rules, guidelines, and exceptions.

This is why I think of them as principles: every situation differs from the last, and there can be no truly hard and fast rules.

The following are the seven principles of software testing:

Software Testing Principles In Details
Software Testing Principles In Details

Testing Shows Presence of Defects

Every software product is delivered to the client or customer once the software tester performs the right amount of testing of various types, such as unit testing, integration testing, user acceptance testing (UAT), and beta testing.

A software product goes through many testing phases because when the software product passes through so many stages of software testing, there will be less chance of a defect.

Exhaustive Testing is not possible.

Before starting the second software testing principle, which is regarding exhaustive testing, it is not possible. we have to learn or know:

What is exhaustive testing?

Exhaustive testing is how we test the software product with all possible data combinations. However, exhaustive testing of software products is not possible.

To understand, let’s take an example: Suppose you are testing a web application, and inside that application, a text box can accept integer values from 1 to 100. so we can do the exhaustive testing by manually entering the amount or using some automation tool.

But if the textbox ranges from 1 to 1 billion, testing with all the values is impossible. You may think that testing by entering manual values is a challenging task, but we can achieve this using some automation testing tools.

If you plan to test with all possible software values, the software testing cost and execution time also increase. So, most software testers do not perform exhaustive testing during software testing. instead of thorough testing, the software testers consider other factors like risk, time, and priorities.

Early Testing

As the name suggests, early testing means all the testing-related activities should be started at the initial stages of software testing development life cycles (SDLC), which is the requirement analysis stage.

If we find any defects, we can quickly fix those defects in the early stage of the SDLC life cycle. It may cost less to correct that defect than if the defects are found in the future phases of the software testing process.

Defect Clustering

Defect clustering occurs during the testing process of software, and you may have noticed that most of the bugs are coming from a specific module of the application. There may be various reasons, such as that particular module being complicated. Coding related to such models is complicated, and there are other reasons.

As per the Pareto principle, also called the 80 – 20 rule, we are getting 80% of defects from the 20% modules, and the remaining 20% of defects are coming from the other 80% of the software.

In this case, you have to concentrate more on our testing on the 20% module, where we are getting more defects or bugs, which is 80% of the total number of bugs.

Pesticide Paradox

This pesticide Paradox principle states that if we repeatedly execute the same number of test cases on a specific duration. Then, these test cases do not help find new defects in the software application or the system.

We must frequently review all the existing test cases to overcome these pesticide paradoxes. If required, then we need to add a new or different test scenario for the implementation of different models of the software application. Doing this will help us find new defects in the software application.

Testing is context-dependent

Testing is a context-dependent principle that means you have seen that software is available for multiple domains, each with many applications. Each application has different requirements, functions, and techniques DTC.

For example, we need to test an eCommerce domain software and follow some specific testing techniques to discover its defect. However, when starting healthcare domain software, we must change our software testing technique to a different process.

This shows that each domain software is tested differently because the software testing is purely based on the context of the domain or the application.

The absence of errors fallacy

If you have completed your software testing process by following many testing methods and testing techniques, you will not see any defects before releasing the software. Then, you can consider that the software is 99% error-free.

But if the software is tested with some wrong requirements, then finding defects and fixing them on time would not help as we have done our testing with some wrong requirements. Finally, the software is not addressing business needs.

For example, there is a login scenario. You have found there are many defects in the login module by considering the wrong requirements. You have tested with the wrong requirements, and getting many defects would not help you move the application to the next phase or into the production environment.

Final Words

These are the seven essential principles of software testing. As a tester, you must test whether the developed software meets all the user or client requirements. And whether the box you found during testing is a mandate or not. These many factors must be considered before delivering or releasing the software to the market.

This post has discussed seven principles of software testing or software engineering. Which comes under manual testing? If you are new to manual testing, we suggest you go through all the manual testing tutorials.

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I love open-source technologies and am very passionate about software development. I like to share my knowledge with others, especially on technology that's why I have given all the examples as simple as possible to understand for beginners. All the code posted on my blog is developed, compiled, and tested in my development environment. If you find any mistakes or bugs, Please drop an email to, or You can join me on Linkedin.

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