What is System Testing

What is System Testing and why is it used?

Software development involves several steps and phases, from initiating an idea until it's eventual release to the market.

System testing is one of several quality assessment checks in software testing. Although the types of checks run within projects vary, no reputable organization skips system testing.

What is System Testing?

Software testing consists of various tests run during different phases of product development. After development, the product undergoes several rounds of reviews and testing to confirm that the built software is market-ready and meets the specified requirement.

When development starts, the developers perform Unit Testing to test individual components to ensure each unit of code works as it should. Unit testing is the initial testing for any software.

The next test level is Integration testing, a process to test all integrated interactions between all the involved systems. Integration testing helps identify issues related to data flow from source to destination.

We then reach System Testing, which is the first opportunity to examine the complete system by checking all integration components and the system as a whole. If only unit and integration testing took place before an item release, there would be a high likelihood the product would not run. Therefore, assessing the entire integrated product is necessary. System Testing is an easy-to-do black box technique that does not require the tester to understand code.

Purpose of System Testing?

System Testing helps to identify both functional and non-functional issues and can uncover defects as well as prevent them. Problems discovered during this phase can include:

  • Incorrect or missed functionality
  • Differences between actual and expected behavior based on requirements
  • Compatibility with different environments
  • Recoverability when the system fails
  • Data access and exposure to unwanted resources
  • Poor performance and usability levels
  • Issues with the overall software user experience

What is System Testing

Key points to consider

System testing is an essential technique for delivering products that match the required specifications. Let us look at some key considerations to be aware of while planning the tests.

Understand Entry Criteria

System testing depends on the unit and integration test results and starts once the development team confirms Unit Testing has passed. When a ticket or task is marked as ready for QA or the team receives an indication to start, it does not necessarily mean that system testing begins at this point. Because it is the end test that will confirm that the built product matches the specified requirement, it requires the build to be completely ready.

The planning and test case creation starts during the initial stage of the Software Testing Life Cycle (STLC). Still, the execution depends on product readiness and the completion of unit and integration tests.

Determine which type of System Tests to run

Before signing off and declaring all testing as passed, the QA team will examine the software from every aspect; functional, non-functional, performance, security, usability, compatibility, scalability, etc. All these different assessments are a part of system testing. Therefore, it is essential to determine which forms of testing will give maximum coverage and final output depending on the category of the developed software.

Test using Actual Data

System Testing is the last stage before handing over the software to end users for User Acceptance Testing. Its aim is to identify all possible bugs that may eventually cause problems for end users, enabling them to be timely addressed. In addition, testing with an actual data set eases the real-world simulation and helps encounter those issues early during the testing phase.

Include tests to cover Different User Roles

Users are exposed to the software at various levels with different permissions. Sometimes, the software will work fine for one user and create a problem for another. Incorporating scenarios that run as different users with varying access levels as part of system testing provides more scope for uncovering issues.

Test Error Handling and Messaging

Creating software that never encounters errors is close to impossible. All error messages supported within the system must be user-friendly and easy to understand. Some errors encountered are user-generated, and some could be system or network errors. As part of system testing, including checks that touch all error situations and check the messaging by intentionally triggering the error conditions can be helpful.


Finally, apart from capturing major bugs in every aspect, system testing is a great indicator and gives a good picture of the final product. System testing evaluates the entire software, builds confidence, and helps decide whether the software is ready for release and handed over for acceptance testing.

Priya Rani

Priya Rani

An Enthusiastic QA Expert who loves to share knowledge and experience through blogging.