System testing is testing the integrated system as a whole with all the units and functionalities (instead of individual modules) that are requested to uncover requirement errors. It is carried out to confirm all system elements behave as intended and all functions are achieved. System testing goes after integration testing as the last step before handing the software over to a user for acceptance testing. It is mainly a black box technique or sometimes a mix of white box and black box techniques.

Here we will try to explain why system testing is important. Saying about “System testing” we mean it is one of the critical parts of a project. It reflects whether the product works from both technical and business perspectives. It involves testing the requirements – requirements specifications (expected behavior of the system or software application) and system specifications (expected design). Let’s get a better understanding of what is system testing with example of a concrete project.

Imagine you have an e-Commerce platform. In this case, system testing would look like reviewing everything in the entire system – from registration to checkout pages with all the functionalities given to a customer. They are integrated and tested overall. System testing simulates how the end customer is going to use the application in real life – logical steps from beginning to end. Is the performance of the application affected negatively by its elements in any manner possible? Can it handle unfavorable conditions and keep functioning at a certain level of effectiveness? Defects that have not been uncovered in other types of testing can be brought to light during system testing. Perfect technical and functional performance as well as bugs related to the security of the app and any sensitive data that can be exposed are a priority. The end-to-end flow (from beginning to end) is reviewed.

Users perform system testing indirectly just by using the product. The QA testing environment and the production environment must be similar for testers to be able to conduct the checkup correctly. Under system testing, we mean either testing an application as a whole or the interaction of an application with external applications, which is called system integration testing. For example, monitoring the operation of an e-commerce application interacting with an external payment gateway service.

Let’s find out what is the purpose of system testing in software development in short?

The primary goal is to ensure the technology works not only technically but for a business as well, from a requirements perspective. Does the software do what it is intended to do? Finding bugs and improving technically is important, but the requirements’ traceability is something that should never be overlooked. With system testing, you have a view of how the product is going to behave after integration into a broader system in which it is used by a customer. Now let’s see how many types of system testing are there in total?

Types of System Testing

There is a diverse variety of tests that can be conducted within the system testing level. Ideally, all of the following techniques and activities related to them should be applied. In practice, it is challenging to implement over 50 different techniques in a single project. So, what are the types of system testing most companies normally use? They are:

• Sanity testing
• Documentation testing
• Installation testing
• Functional testing
• Load testing
• Security testing
• Usability testing
• Accessibility testing
• Performance testing
• Migration testing
• Adhoc testing
• Compliance testing
• Reliability testing
• Recovery testing
• Stress testing
• Scalability testing
• Regression testing

Every project is unique, which means it requires different techniques, tools, and involvement, though the basics will always remain consistent. The more you go beyond the ordinary approaches, the better possible outcome you get. The more techniques of system testing are involved in the process, the more analyzed and polished your product is.

How to Implement System Testing?

To conduct system testing, all modules should be ready. The process starts the moment the system is analyzed from the perspective of how it is configured. Every individual piece should work well. Then, it becomes more comprehensive with an end-to-end checkup when you start analyzing all the way through from both technical and business perspectives to see whether the flow of the process acts as intended.

As with any other type of testing, having an applicable relevant document with the objectives and the software information included is essential for the process. Updated requirements and expectations should be enlisted. Both functional and business requirements analyses are done in system testing. A test plan is required for a person who is responsible for system testing to get a better insight into the project’s scope. Then, the test cases and scripts with the desired outcome are added, and the testing environment is created. Testing begins. Every bug is reported and re-tested once again. Then, regression testing (to confirm that recent improvements do not influence the existing functionality) is carried out, and the procedure is repeated until the application is ready for deployment.

The process itself is planned and structured. The following steps are accomplished.

1) Test plan preparation
2) Test case generation
3) Test environment setup
4) Test cases implementation
5) Defect reporting
6) Regression testing
7) Defect resolution
8) Retesting

Solid documentation with clear requirements (to design test cases properly) and with all actual results achieved during this type of testing is included. What determines system quality after system testing is over? The main criteria are:

• Performance, which is an adequate response time, processing speed, and efficiency.
• Maintainability, which is measured by how efficient the documentation is.
• Modifying or removing functionalities without breaking the system down.
• System response to a user’s action under normal and increased load conditions.
• System security, which includes data encryption and network attack protection that satisfy expected requirements.
• The ability to run the product on as many platforms as stated.
• Recovery behavior, which is how fast the application moves back to the initial state after crashes or hardware breakdowns.

So, what is the need of system testing and why is it so important?

Advantages & Disadvantages of System Testing

System testing should not be treated superficially as it is the final step before you can determine whether everything in your application is set up the way it should be to satisfy end users and get their approval.

Advantages of System Testing

With the aid of system testing, the compliance of the system workflow with specific requirements can be verified, and the overall confidence in the product, both of the team and customers, can be boosted. This is why system testing is so important and what exactly you get by analyzing a project from its perspective:

• Risks and bugs related to system behavior in a specific environment are minimized or eliminated. Hidden problems are easily revealed.
• The flow of data for every task and process is involved. The behavior of all integrated pieces is reviewed.
• Security, recovery, maintainability, external interface, certification requirements, and complex functionality assessment are the main focus.
• Black box technique does not need an understanding of programming language and good technical skills for effective implementation. The focus is on the user’s perspective.
• The team members have their benefits in how they perceive the product that they are working on. A deep level of testing influences the level of confidence the team has before introducing the product to the market.

Though system testing is beneficial for any project, it has its disadvantages or it is better to say hidden difficulties that have to be taken into account.

Disadvantages of System Testing

• Extensive functional knowledge of the system under test is required.
• Since all functions combined as one entity should be covered with tests, system testing requires more time and dedication. The cost increases as well.
• It requires smart debugging tools as well as skilled specialists to find the hidden errors.