Seven Principles of Software Testing

You must achieve optimum test results while conducting software testing without deviating from the goal. But how do you determine that you are following the right strategy for testing? For that, you need to stick to some basic testing principles.
Here are the seven common testing principles that are widely practiced in the software industry.

7 Principles of Software Testing

  1. Testing shows the presence of defects

  2. Exhaustive testing is not possible.

  3. Early testing

  4. Defect clustering

  5. Pesticide paradox

  6. Testing is context-dependent

  7. Absence of errors fallacy

Exhaustive testing is not possible

Yes! Exhaustive testing is not possible. Instead, we need the optimal amount of testing based on the risk assessment of the application. And the million-dollar question is, how do you determine this risk? To answer this, let’s do an exercise In your opinion, Which operation is most likely to cause your Operating system to fail?
I am sure most of you would have guessed, Opening 10 different applications simultaneously. So if you were testing this Operating system, you would realize that defects are likely to be found in multi-tasking activity and need to be tested thoroughly, which brings us to our next principle Defect Clustering

Defect Clustering

Defect Clustering states that a few modules contain most of the defects detected. This is the application of the Pareto Principle to software testing: approximately 80% of the problems are found in 20% of the modules. By experience, you can identify such risky modules. But this approach has its problems
If the same tests are repeated over and over again, eventually the same test cases will no longer find new bugs.

Pesticide Paradox

Repetitive use of the same pesticide mix to eradicate insects during farming will, over time, lead to the insects developing resistance to the pesticide, Thereby ineffective pesticides on insects. The same applies to software testing. If the same set of repetitive tests are conducted, the method will be useless for discovering new defects. To overcome this, the test cases need to be regularly reviewed & revised, adding new & different test cases to help find more defects.
Testers cannot simply depend on existing test techniques. He must look out continually to improve the existing methods to make testing more effective. But even after all this sweat & hard work in testing, you can never claim your product is bug-free.

Testing shows the presence of defects

Hence, the testing principle states that – Testing talks about the presence of defects and doesn’t talk about the absence of defects. i.e., Software Testing reduces the probability of undiscovered defects remaining in the software, but even if no defects are found, it is not a proof of correctness.
But what if you work extra hard, taking all precautions & making your software product 99% bug-free? And the software does not meet the needs & requirements of the clients.

Absence of Error – fallacy

Software that is 99% bug-free may still be unusable. This can be the case if the system is tested thoroughly for the wrong requirement. Software testing is not merely finding defects but also checking that software addresses the business needs.
The absence of Error is a Fallacy, i.e., Finding and fixing defects does not help if the system build is unusable and does not fulfill the user’s needs & requirements.

Early Testing

Early Testing – Testing should start as early as possible in the Software Development Life Cycle. So that any defects in the requirements or design phase are captured in the early stages.
Fixing a Defect in the early stages of testing is much cheaper. But how early should one start testing? You should start finding the bug when the requirements are defined.

Testing is context-dependent

Testing is context, which means that the way you test an e-commerce site will be different from how you test a commercial off-the-shelf application. All the developed software is not identical.
Depending on the application type, you might use different approaches, methodologies, techniques, and testing types. For instance, testing any POS system at a retail store will be other than testing an ATM.

In this Software Testing Tutorial, we will learn seven principles of software testing. Understanding these seven principles of software testing is very important in order to understand software testing.

In this testing tutorial I will try to explain these 7 testing principles with real testing scenarios so you can easily understand and explain them in software testing interviews.