Introduction to Software Testing Principles
Software Testing Principle is a process of testing the result or output of a product with an expected output of a client. In other words, we can say that evaluation of system or components to find the specified requirements. It executes the process of identifying the gaps, errors, any defects in the product, quality of software being developed, completeness or missing requirements to match specified requirements.
Before moving to software testing principles, we will see briefly some concepts of software testing as discussed below:
Software Testing History
The testing of the product began in the year 1979 by Glenford J. Myers who introduced the process of debugging the products. His main intention was to work on breakage testing which is a simple test case to detect undiscovered error and to separate fundamental development activities, such as debugging, errors, etc. from the software engineering community.
Who does Testing?
In big industries or companies, there will be a team of associated stakeholders of the project to conduct the testing based on the process. They will analyze the software on the given requirements.
Following are the professionals who involved in a testing process depending on their respective capacities:-
- Software Tester
- Software Developer
- Project Manager
- End User
There are different types of roles who test the software or product based on their experience and knowledge such as Software Tester, Software Quality, Assurance Engineer, QA Analyst, etc.
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Principles of Software Testing
Software testing is an extremely challenging task. The principles of software define instructions for development teams to find the errors or effects of a project. Following are the seven fundamental principles of software testing:-
Principle 1: Testing shows the Presence of Defects
Testing is a process which shows the presence of defects in the application. It shows the defects but cannot prove that there are no defects. Meaning that the testing team cannot say that the product is 100% defect free. It reduces the number of undiscovered defects in the application. You cannot assume that the tested application is 100% error free, even though testing is done. Therefore, design the needed test cases to find the defects as much as possible.
Principle 2: Exhaustive Testing is Impossible
There is less possibility of testing with combinations of inputs, data, test scenarios, and preconditions as they will take more time to test the process. Therefore, the testing team can use some important testing criteria effects such as risk and priorities instead of doing exhaustive testing.
For instance, consider there are 15 fields in one screen which contains 5 possible values. To test all combinations, you would need 30 517 578 125 (515) tests. But, project timescales would never allow testing a large number of combinations. Because of this reason, test effects called risk and priorities are used to test important features. So, accessing and managing risk is considered as the most important and essential activities for testing in any project.
Principle 3: Early Testing
In this stage, testing activities will be conducted in the software or system development life cycle to find the defects as soon as possible and to focus on defined objectives. Testers can start testing the products if they have the availability of product requirements or documents.
The main advantage of early testing is testers can easily detect errors, bugs, and help in each level of development with fewer costs and efforts.
If errors are found in an initial stage of the development life cycle, then it will be easier and cheaper to fix, and also the cost of quality will be less. Otherwise, if they found late then you need to change the whole system process. The testing team will have a deep understanding of the product as they were involved from the beginning of the requirement gathering and analysis phase.
Principle 4: Defect Clustering
This phase includes defects related to a small number of modules, which are tracked during pre-release testing. It means that small modules will have more defects in the system. In the Pareto Principle application, software testing is approximately 80:20; which means 80% of the problems are found due to 20% of the modules.
Defect clustering uses knowledge and experience of the testing team to recognize the potential modules to test. That forecast can help save time and effort as the team only needs to focus on those “sensitive” areas. There is a small drawback of this phase when testers focus on a small area of the team, they may fail to miss the bugs from other areas.
Principle 5: Pesticide Paradox
This phase is used to review test cases systematically and uses different types of tests to find more defects of the software or system. If you are running the same tests again and again, then there is less chance of getting new bugs which are discovered by these test cases.
You cannot apply these tests to the whole system but can be applied to some limited modules. Testing teams will often review and update the test cases in order to cover different types of sections of the projects.
Principle 6: Testing is Context Dependent
Testing is basically content dependent, projects and products include different elements, features, and requirements. In this approach, different types of sites can be tested differently and the same test cases cannot be applied for different projects.
For example, safety and critical software will be tested differently than an e-commerce site or an application in the banking industry will be tested more than entertainment software. There are different types of methodologies, techniques, and types of testing based on the nature of an application.
Principle 7: Absence of Errors Fallacy
If there is an absence of errors in the application, or if the system built is unusable and does not meet the user’s expectations, then finding and fixing defects will not help. If there are no bugs in the software, then you should not consider that software is ready to be used; because testing should be conducted along with the right requirements.
Conclusion: Software Testing Principles
So far, you have seen that seven principles of software testing provide reliable product quality by testing the products. These principles can be applied for testing the project and coding. The main objective of this life cycle process is to find correctness, completeness, quality and detecting errors in the software.
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