7 principles of software testing
Software testing is one of the major steps involved in writing error-free code. It involves the process of executing a program with the aim of finding an error. When testing is done correctly, the found errors can be successfully removed from the software. In this article, we will look into the seven basic principles of software testing that are used in the software industry.
These basic principles have been collated and popularly recognized as the absolute core of testing after several years and the evolution of testing and software development.
The seven principles of software testing include:
- Testing shows the presence of defects
Software Testing helps to show the presence of defects and reduces the likelihood of undiscovered defects in the software. Quality Assurance engineers are in charge of testing to make sure of this and the major goal in mind is to make the software fail. Software testing shows the presence of these defects, it proves that defects are present but it can not prove that software is defect-free. Testing can help to reduce the number of defects but not remove all defects. Even multiple testing can never ensure that software is 100% bug-free. Also, if no defects are found, it is not proof that the software is defect-free.
- Exhaustive testing is not possible!
When it comes to software testing, exhaustive testing is an impossible task to achieve. It is simply impractical to test all the functionalities and all the valid and invalid combinations of input data during actual testing. The cost and time implication of indulging in exhaustive testing is also one of the reasons why it should be avoided. Instead, just the right amount of testing based on the risk assessment of the application is needed.
In place of attempting the already impossible exhaustive testing where most of the efforts would turn out to be ineffective or unsuccessful, a few combinations in the software are considered based on priority using different techniques and then tested. In short, only a few test cases can be tested while the rest is put under the presumption that the software is accurate and it will produce the expected output in every test case.
3. Early Testing
Early testing is highly encouraged when it comes to software testing. Testing should be done as early as possible in the software development life cycle (SDLC). This is because the defect can be easily detected in the early phases of software development and treated at a cheaper cost rather than waiting till the future phase of the testing.
For better performance, testing the software for bugs should start as soon as the requirements are defined so that any defects in the requirements or design phase are captured in the early stages. Early testing can also help in completely avoiding defects and prevent the code from being re-written, which might lead to overruns and missed deadlines. Not to talk about the quick, timely and continuous feedback loops. When a team encounters limitations or restrictions, early feedback is one of the best ways to overcome these, and testers are essential for this.
4. Defect clustering
This is the Pareto Principle of software testing. This principle suggests that 80% of software defects come from 20% of the modules. Now you must be wondering how this relates to defect clustering. Defect clustering means that the defects found during testing can be related to a small number of modules. In a project, a small number of modules can contain most of the defects. There might be multiple reasons for this like the modules may be complex, coding related to such modules may be complicated etc.
5. Testing is context-dependent:
Testing is context-dependent means that the testing approach to the software depends on the context or domain in which the software is developed. These domains are tested differently because they each have different requirements, functions, risks e.t.c. For example, the testing of an advertising site is different from the testing of a banking application. This means that testing is purely based on the context of the domain or application.
6. Pesticide Paradox
The pesticide Paradox principle says that if the same set of test cases are executed again and again over a particular period of time, these sets of repetitive tests will not be able to effectively identify new defects in the system.
In order to overcome this principle, the set of test cases needs to be regularly reviewed and revised. And new test cases should be added where needed to help find more defects. This might require the existing test cases to be deleted, but it guarantees a better result. This is why testers cannot continually depend on existing test techniques. They have to keep looking out to improve the existing methods and make testing more effective. But even with all these, you don’t get to claim that your product is bug-free.
7. The absence of errors is a fallacy
That the software application is 99% bug-free is not the only requirement needed to know if the software is usable. If the software does not meet the customer/consumer requirements, then it is simply unusable. It is necessary that software is 99% bug-free but it is also mandatory to fulfil all the customer requirements.
In summary, Software Testing is an important step in SDLC as it verifies if the software is working and meets the end-user needs. It identifies as many defects as possible and provides room for plenty of improvement. These seven principles of software testing are the known pillars of testing and should be followed meticulously in order to avoid making serious mistakes or incurring a huge cost on the project.