7 principles of software testing that every software tester should know

Software testing is a way of verifying that the software is working according to the needs of the end user. The basic principles of software testing are known as the pillars of testing, and thanks to them, a tester can effectively detect as many bugs and defects as possible. In this article you will learn how the seven principles of software testing work and why every IT tester should adopt them.

Software development consists of several stages and complex procedures, which also bring many software bugs. When testing the software, the IT tester must follow procedures and policies to ensure that the software is tested effectively, in the shortest possible time and with a positive result.

There are seven basic principles of software testing that have been adopted by International Software Testing Council (ISTQB). These principles serve to achieving optimal results without deviating from the objective of the test. Individual software testing principlesthat every professional software tester should know are:

1. Testing proves that there are bugs in the software

Each application goes through different testing phases, such as integration tests, system tests, regression tests or acceptance tests. The primary purpose of software testing is identify the number of yet unknown errors using the chosen method and testing techniques. The IT tester tries to find as many hidden system bugs as possible, and then the developers work on fixing them.

The first of the basic principles of testing states that no bug-free software exists and testing reveals the presence of defects, not their absence. Sufficient and repeated testing only reduces the incidence of bugs, and the fact that testers find no software bugs in repeated testing does not mean that the software is bug-free. Some hidden bugs in software are only discovered by the user in the production environment of the application or software when using functionalities or variations of functionalities that are not commonly used. And that is why testing detects the presence of defects, not their absence.

IT software tester identifies software bugs behind the computer
Software testing indicates the presence of a bug, not its absence.

2. Exhaustive testing is not possible

Testing each function using all valid and invalid inputs and assumptions is known as full or exhaustive testing. During software testing it is difficult and almost impossible to test all functions and all possible combinations of use. Instead, priority isto test a few combinations that are evaluated to be the most important.

Full software testing would require unlimited effort, time and cost, without meeting the efficiency of testing. Every software development has a designated budget and a final launch date, so testing must also be done in some time frame. The second principle of software testing states that exhaustive, or full testing is not possible. It is recommended to start testing in the early stages of development and to test the software using several methods such as equivalence partitioning and boundary value analysis.

3. Early Testing Principle

Early testing means that all testing activities should start in the early stages software development life cycle (SDLC). If IT testers are involved in software testing early in the SDLC, software bugs can be identified and fixed in the early stages, which reduces the overall repair costs ofsoftware bugs.

4. Pareto rule and the accumulation of IT software errors

When testing any software, IT testers are faced with the situation that most of the defects found are related to some specific functionality. This may be because the application is very complex, the programming is too complicated, or the software developer has made a mistake. Certain software modules contain the highest number of bugs or generate the most software bugs.

Pareto’s rule states that 80% of the problems come from 20% of the modules. Therefore, the emphasis is on testing 20% of the modules, where the software faces 80% of the bugs. Defect clustering rule calls for the defect-prone area of IT software to be thoroughly tested, which should significantly reduce the number of defects.

Hands of two IT software testers show code on monitors during defect clustering rule
Testing the models that generate the most bugs will reduce the number of bugs.

5. The pesticide paradox and its negative impact on testing

When IT software tester encounters a module that has a larger number of bugs, he devotes additional hours of testing to that module. After the defects are removed by the developers and after several test iterations, the code quality improves and the number of defects decreases. However, it may happen that with increased interest in one module, the developer may neglect other modules. The pesticide paradox is thus a principle that says that as long as the same kinds of tests are repeated over and over again, these tests will not find any new software bugs.

In this case, it is recommended adding new test casesto help find defects in other areas of the software. One of the basic principles of software testing recommends avoiding this problem in two ways:

  1. Write a new set of test scenariosthat will focus on a different area or modules.
  2. Add new test cases to existing test cases.

Using the second approach, the total number of test cases is significantly high and results in more effort and time required for execution. Therefore, it is necessary to check which test cases have failed and which are no longer relevant for testing. It is then possible to remove redundant cases.

6. Testing is related to the type of software

Software application development is a very progressive and fast growing segment. Some of the most in-demand areas of IT development are insurance, banking, healthcare or travel. Each of these software has a different purpose, client requirements and different functions, so they require a specific type of testing designed exclusively for that type of software. It would not be efficient if IT testers used the same technique and type of testing to test all types of applications.

The sixth rule of software testing therefore reminds us that all testing depends on the context of the application and software testers must use specific types of testing, different techniques, approaches, and multiple methods to check.

7. Absence of bugs does not imply software functionality

When the software has passed the testing phase and no further bugs are found in the software before it is launched, it means thatthe application is 99% bug-free. However, it may happen that the software is tested with incorrect requirements, in which case it may still be unusable. Apart from being error-free, the software must meet the most important requirements, which are the needs of the end user.

The last principle of software testing states that identifying and fixing bugs would not be effective if the application is impractical andunable to meet the client’s requirements and needs.

Software testing is an essential step in the software development life cycle. It verifies that the software is working according to the end user’s needs, identifies software bugs that have occurred, and ensures that the software is safe for users. To make testing as effective as possible, every IT tester should learn the basic principles of software testing and use them in real testing. It is no different here at msg life. If you want to start your career as an IT tester, click on job offerswhich we update regularly, send your CV and come and test insurance software as our new software tester.

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