Software Testing - Levels

The software testing is the one of important processes followed in the software development life cycle (SDLC) to ensure that the software is delivered as per quality. This means that maximum bugs should be detected, and resolved and software should work seamlessly with the customers. In order to achieve this, it goes through various levels of testing.

Different Software Testing Levels

The different levels of software testing are listed below −

Unit Testing

This is the first level of testing done by the developers themselves before handling the software to the testing team to ensure that its individual units are working as expected. It is done to segregate small, individual units of the software and check if they are developed as per the requirements. Thus unit testing is done to catch bugs at the early stages of the SDLC. It identifies the regression defects as well. The effort and cost of doing unit testing is not high, and it helps to confirm if the code developed is working properly.

However, in most situations, it is seen that the unit test fails to detect most of the bugs in the software. Also, it eats up the developers time to design unit test cases.

Integration Testing

This is the second level of testing conducted by the testers to verify if multiple unit tested modules are working together collectively without any defects at the integration or at interface of the modules. It can be done either manually or by automation. It helps to increase the test coverage and identifies the defects that may come up while multiple units are combined. The defects detected at this level are easier to fix, than at later stages.

The time, effort, and resources to carry out integration testing among modules are higher. It requires creation of drivers, and stubs correctly else, they may produce incorrect results.

System Testing

This is the third level of testing where the entire software comprising all the modules, and sub-modules is tested to ensure that all the requirements are fulfilled, and it is working properly in its environment without errors. It is the third level of testing and covers the end to end flow of testing.

The system testing verifies if the software is working as per the system and business requirements. This is a critical level of testing to prevent defect leakage at the production. It requires a huge amount of time, effort, and resources to complete system testing.

Acceptance Testing

This is the fourth and final level of testing done to verify if the software has been built correctly as per the user requirements and fit to be shipped to production. It is done to catch both cosmetic as well as functional defects. It ensures that the software is working as expected in the customer’s environment and it finds bugs or issues just before the software is released to its actual users.

In the acceptance testing, sometimes the software is also tested by the customers themselves, and thus helps in building the customer's confidence, and faith in it. The customers get an idea, and data on how the software may behave with respect to the real life scenarios. Since the acceptance testing is the final level of testing, it requires a lot of planning, and resources to complete it. Any test case can be picked and chosen for acceptance testing by the customers.

Conclusion

This concludes our comprehensive take on the tutorial on Software Testing Levels. We’ve started with describing what the different software testing levels are. This equips you with in-depth knowledge of Software Testing Levels. It is wise to keep practicing what you’ve learned and exploring others relevant to Software Testing to deepen your understanding and expand your horizons.

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