Principles Of Software Testing

Principles Of Software Testing

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Anshuman
Anshuman Singh
Senior Executive - Content
Updated on Jan 3, 2023 10:49 IST

Software testing is complicated and requires significant resources to produce high-quality products. But, have you ever considered how we can be confident that we are employing the proper software testing strategy and that it is the correct way? The ISTQB’s principles of software testing can assist you in this endeavor. But what exactly are these seven software testing principles?

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The ISTQB (International Software Testing Qualifications Board) outlined seven principles of software testing that can help improve the testing process and create higher-quality software or application. So, without further delay, let’s begin exploring these seven software testing principles one by one.

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Table of Content (TOC)

Seven Principles of Software Testing 

The ISTQB (International Software Testing Qualifications Board) outlined seven principles of software testing, which are:

  • Testing shows the presence of defects
  • Exhaustive testing is impossible
  • Early testing
  • Defect clustering
  • Pesticide paradox
  • Testing is context dependent
  • Absence-of-errors fallacy

Let’s explore each of these seven principles of software testing in detail.

Testing shows the presence of defects 

This is the first software testing principle. According to this principle, a software testing technique or strategy can assist you in identifying a bug or defect before releasing the application or software to the general public. However, this does not guarantee that the created software or application is completely bug-free.

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In layman’s terms, this principle states that the testing techniques and the tests conducted by developers, testers, and others can assist you in identifying bugs or defects. But, there is no testing procedure or technique that guarantees that the created software is entirely free of bugs and defects.

Exhaustive testing is impossible

Before diving into this principle, it’s a good idea first to understand exhaustive testing. Exhaustive testing is a type of testing that entails verifying and testing all functionality of a software application using both valid and invalid inputs as well as pre-conditions.

However, exhaustive testing is unrealistic. Testing software or application with valid and invalid inputs, as well as pre-conditions, is impossible. Let us look at an example to understand this principle better. Assume you’ve written an application that accepts numeric input from 0 to a billion. You can no longer test the output for each value as it would be time-consuming and would increase the testing cost.

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As a result, careful planning and assessment are required before testing software or application. It ensures that your test coverage is adequate and that you can be confident in the final product without having to examine each piece of code.

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Early testing 

Regarding the software development lifecycle, early testing is critical for identifying defects or errors in the requirements, functionality, or design phases.

In order to start testing early, various developers choose to use the static testing technique. Static testing allows you to test for glitches or faults in the application without running the code. This enables developers and testers to identify bugs or defects early in the software development life cycle, saving time, hard work, and funds.

According to this software testing principle, fixing bugs early in the testing process is much easier and less expensive than at the end of the software lifecycle. Changes to the code, design, functionality, and so on can be costly in terms of both money and time. As a result, early testing is critical and should begin as soon as possible.

Defect clustering 

This software testing principle states that specific software units, modules, or components contain the most bugs or defects and end up causing the majority of operational errors. In layman’s terms, this principle states that most of the defects detected are contained in a few modules.

Knowing this could be very useful for software testing because there is a good chance that if we find one problem in a specific module or region, we will find numerous others in that area. We can also focus our testing on various other factors, such as the complexity of the software, the number of modules, third-party dependencies, and so on. 

Because these areas are more likely to have defects, focusing on them may help you find the majority of bugs in your application. And the Pareto principle also states the same thing – 80% of the issues are found in 20% of the components.

Pesticide paradox 

This software testing principle is based on the theory that when a farmer uses the same pesticide repeatedly on the same crops to eliminate pests, the pests eventually develop immunity, rendering the pesticide ineffective. The same applies to software testing.

In software testing, the pesticide paradox refers to repeatedly performing the same test cases in order to find bugs or defects. But, using the same test cases, again and again, will eventually fail in identifying new bugs in the software.

As a result, to overcome the pesticide paradox situation, test cases must be reviewed and updated regularly so that new and more flaws can be discovered. To enhance the effectiveness of testing, the testing team must consistently explore ways to enhance existing test methods or create new test cases to verify the software.

Testing is context dependent 

Is it possible for a doctor to use the same medicine to treat two patients with different problems? To make it more simple and understandable, answer the following question: Can a medicine, Dollo (a standard fever medicine), treat heart disease? The answer will be negative. The same is true for software testing.

According to this software testing principle, no single software testing approach will fit every type of software. Hence, different testing techniques should be used for different types of software.

For example, an e-commerce website may require different testing and approaches than a database reporting application. Hence, testing strategies or techniques must change depending on the context of the application, i.e., the type of application or software being tested.

Absence-of-errors fallacy 

Let’s say the created software is 99% bug-free, but it doesn’t provide the features and functionality that the client requested. This makes the created software  a total waste. Even bug-free software will be rendered useless if it fails to meet the needs of the business.

As a result, running tests relevant to the system’s requirements is critical because software testing is about more than just finding bugs. It also guarantees that the software will meet the user’s requirements and expectations.

You can test against early prototypes during the usability testing phase to get feedback from users that you can use to ensure the software is usable and that the software will fulfill the users or business requirements.

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Conclusion

In this article, we looked at the seven principles of software testing.  To summarise all of these software testing principles, let’s look at them in a tabular format with simple explanations.

Here’s the table:

Principle of Software Testing Explanation
Testing shows the presence of defects This principle of software testing states that software testing can help identify bugs or defects but cannot guarantee that the software tested is entirely bug-free.
Exhaustive testing is impossible This principle of software testing states that it is impossible to test the whole software from every angle. Hence, the maximum test area should be identified and tested in order to be confident regarding the final product without having to examine each piece of code.
Early testing This principle of software testing states that testing should start as early as possible in order to develop high-quality software or applications.
Defect clustering This principle of software testing states that specific software units, modules, or components contain the most bugs or defects and end up causing the majority of operational errors. Hence, those areas should be thoroughly tested.
Pesticide paradox This principle states that test cases must be reviewed and updated regularly to discover new flaws rather than repeatedly using the same test cases and strategies.
Testing is context dependent This principle of software testing states that no single software testing approach will fit every type of software. Hence, different testing techniques should be used for different types of software.
Absence-of-errors fallacy This principle of software testing states that even though your software is 99% bug-free, it should also deliver the features and functionality that the client requested; otherwise, it is a waste.

If you have questions about the topic (Principles of Software Testing), please leave them in the comments section. We will gladly assist you.

Happy Learning!!

FAQs

What are the fundamental principles of software testing, and why are they important?

The fundamental principles of software testing include thoroughness, early testing, systematic approach, defect clustering, and Pesticide Paradox. Understanding these principles is crucial for achieving effective and efficient software testing processes.

How does early testing contribute to better software quality, and when should it be initiated in a project?

Early testing allows for the identification and resolution of issues at an early stage, reducing the cost and effort required for bug fixes later in the development process. It should begin as soon as requirements are available.

What is the significance of the systematic approach in software testing, and how can it be implemented?

A systematic approach ensures that testing is organized, well-documented, and follows a defined process. It involves test planning, test case design, execution, and reporting, with each step carefully structured for efficiency and reliability.

What is the Pesticide Paradox in software testing, and how can it be addressed?

The Pesticide Paradox states that if the same set of tests is repeated over time, it becomes less effective at finding new defects. To address this, testing should be regularly reviewed and updated with fresh test cases to uncover evolving issues.

How can software development teams implement the principle of defect clustering to improve their testing efforts?

Defect clustering suggests that a small number of modules or areas in software tend to contain a majority of defects. Teams can focus their testing efforts on these modules and areas to uncover and fix the most critical issues.

About the Author
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Anshuman Singh
Senior Executive - Content

Anshuman Singh is an accomplished content writer with over three years of experience specializing in cybersecurity, cloud computing, networking, and software testing. Known for his clear, concise, and informative wr... Read Full Bio