Types of Functional and Non-Functional Testing

Modern companies understand that software quality directly depends on a comprehensive approach to testing. This is why increasing attention is being paid to both functional and non-functional testing. Advanced tools and technologies are used to identify system weaknesses and ensure its readiness for real-world use. Different tools are used for different tasks: Selenium is suitable for automating functional tests, LoadRunner for analyzing the performance of corporate systems, and Gatling for flexible load testing. JMeter cloud load testing allows you to simulate the behavior of thousands of users in the cloud and obtain the most realistic picture of application performance under high load. To ensure that such tests deliver practical value, companies are increasingly entrusting them to reliable companies with QA experience, such as PFLB.

Functional Testing

Functional testing is the process of testing the functionality of software, as a result of which the actual behavior of the system is compared for compliance with the functional requirements of the customer.

What Are the Levels of Functional Testing?

There are four main levels for functional testing (sometimes they are also called types of functional testing):

1. Unit testing — most often performed by developers. This is an example of functional testing, where a certain isolated application module is tested in its own limited environment. No external factors and relationships with other software modules are taken into account at this level of testing.
2. Integration testing — a level of testing that checks how individual components can interact with each other, without taking into account external factors.
3. System testing — a level of testing that checks the functionality of the software as a whole. It can be said that at this level, the actual behavior of the system is compared for compliance with the customer’s functional requirements.
4. Acceptance testing is the final level of testing, which is usually carried out by the customer or their representative, and can also be carried out by the end user. It is carried out in order to obtain an assessment of the readiness of the software and its compliance with the customer’s requirements.

To individual types of testing, we can add those that need to be performed in the event that changes are made to the product.

These can be the following types of testing:

1. Regression testing is a type of software testing that is carried out after changes are made to it. Before testing, a list of test cases is selected, according to which the software will be evaluated for the appearance of new deviations, as well as for the fact that the previous functionality is working properly and without changes.
2. Smoke testing is a type of software testing that checks the basic functionality, i.e., checking that the main functions of the program work without deviations and errors. This allows you to move on to testing narrower modules and areas of software operation.
3. Sanity testing, like smoke testing, checks the main key functionality, but not so deeply. The priority is to check the key areas that may be affected by changes and new features of your software.
4. Adaptation testing involves checking that the software successfully adapts to new requirements that have arisen as a result of the changes.
5. Patch testing is carried out if the changes are provided in the form of a patch or update. Their correctness and stability are checked. The main goal is to check that the updates are installed without failures and do not lead to unwanted side effects and bugs.

These are far from all types of testing that may be associated with software changes.

Non-Functional Testing

Non-functional testing is a type of testing that checks the features of the software that are not related to functional testing. In comparison, functional testing checks what exactly the end user can do with this product, and non-functional testing checks how the system works and what characteristics it exhibits during its operation.

Main types of non-functional testing:

1. Performance testing. The following types of testing can be attributed to performance testing:

• Load testing — the process of testing the system with a minimum load, with a subsequent increase in the load to the maximum. It is necessary to identify its possible operating limits.
• Stress testing — testing the system at maximum loads, as well as those that exceed the maximum allowable load of the system. It is carried out to monitor how the system will react to overload, or to identify points of failure.
• Recovery testing — testing how a system can recover from a failure.
• Stability testing – testing a system over a long period of time under average load, aimed at identifying possible shortcomings related to resource leakage, error accumulation, or other factors.
• Load time testing — testing how quickly a system copes with loading various resources (web pages, databases, applications).
• Resource performance testing — evaluates the resources used (RAM, network bandwidth, network processor load, etc.).
• Scalability testing — testing a system to maintain software performance and availability under conditions of increased load or volume of processed data.

2. UI testing — checking the user interface for correct display, graphic design, compliance with functional features, as well as the process of interaction of the end user with the program.
3. UX testing — checking the comfort and clarity of using the product for the end user.
4. Installation testing is the process of checking the procedure for installing software on any device for which it is intended. This type of testing may also include the process of checking the uninstallation of your software.
5. Security testing is the process of checking software for vulnerabilities, risks, and threats. The main goal is to prevent information and confidential data from being obtained by attackers.
6. Compatibility testing is checking how well the software is able to work correctly with different operating systems, in different browsers, as well as on different devices and in different environments.

Various tools are used to conduct functional and non-functional testing, including JMeter, Selenium, LoadRunner, Gatling, etc.

Conclusion

Functional and non-functional testing is the foundation of any digital product’s quality. PFLB has established itself as a reliable partner in this field, offering a modern suite of services: JMeter load testing in cloud for migrating scenarios to the cloud, Website Load Testing for verifying the stability of web services, API Load Testing and gRPC Load Testing for analyzing interface performance, and intelligent AI Reports that simplify the interpretation of results. This comprehensive approach allows businesses to obtain not just load data but also comprehensive optimization recommendations, making PFLB a strategic ally in creating stable and scalable solutions.