System Testing in Software Engineering

system testing

What is System Testing?

System Testing is defined as the testing of a fully complete and integrated software product. Usually, the software is only a single element of a bigger computer-based system. Ultimately, the software is an interfaced with any other software/hardware systems. System Testing is actually a series of some different tests whose single purpose is to exercise the computer-based system.

Two Category of the Software Testing are –

  • Black Box Testing
  • White Box Testing

System test usually falls under the black box testing category of software testing.

White box testing is the method of testing the internal workings of the code of a software application. In contrast, the black box and System Testing are opposite to each other. Where system test usually involves the external workings of the desired software from the user’s perspective.

What do you verify in System Testing?

This kind of testing involves testing the software code for the following

  • Testing the fully complete integrated applications and including the external peripherals in order to check how the components will interact with one another and with the desired system as a whole. This is also called as End to End testing scenario.
  • Verify through the testing of every recognizable input in the application to check for the desired outputs.
  • It includes testing of the user’s experience with the desired application. 

That is a very simple description of what processes are involved in system testing. You need to build many detailed test cases and some test suites that can test each and every aspect of the application as seen from the outer without even looking at the actual source code. 

Software Testing Hierarchy

As with most of the software engineering process, software testing also has a prescribed order in which all the things should be done. The following is a basic list of the software testing categories that are arranged in chronological order. These are the steps and ways taken to fully test the new software in preparation for marketing it:

  • Unit testing – testing that is performed on each module or the block of code during the development process. Unit Testing is usually done by the programmer who writes the code.


  • Integration testing – testing that is done before, during and after the integration of any new module into the desired software package. This usually involves testing of each and every individual code module. One single piece of software can easily contain several modules which are often created by the different programmers. It is very crucial to test each and every module’s effect on the entire program model.


  • System testing – testing that is done by some professional testing agent on the completed software product before it is actually introduced to the market.


  • Acceptance testing – beta testing of the product is done by the actual end-users.


Different Types of System Testing

There are more than 50 types of System Testing. Below we have some listed types of system testing used by a large software development company

Usability Testing – Usability Testing mainly focuses on user’s ease to use all the application, providing flexibility in handling all the controls and ability of the system to meet its desired objectives


Load Testing – Load Testing is very necessary to know that a software solution will perform under real-life loads.

Regression Testing- – Regression Testing usually involves testing that is done to make sure that none of the changes made are over the course of the development process and may have caused new bugs. It usually makes sure that no old bugs appear from the addition of any new software modules over time.

Recovery Testing – Recovery testing is basically done to demonstrate if a software solution is reliable, trustworthy and can easily recoup from the possible crashes.

Migration Testing – Migration testing is also done to ensure that the new software can be easily moved from the older system infrastructures.

Functional Testing – It is also known as the functional completeness testing, Functional Testing usually involves trying to think of any of the possible missing functions. Testers might make a complete list of all the additional functionalities that a product could have to improve itself during functional testing.

Hardware/Software Testing – IBM refers to the Hardware/Software testing as “HW/SW Testing”. This is done when the tester focuses his/her attention on all the interactions between hardware and the software during the system testing.

What Types of System Testing Should Testers Use?

There are more than 50 different types of system testing. The specific types can be used by a tester depend on various variables. Those variables may include:

  • Who the tester works for – This is a very important factor in determining all the types of system testing that a tester will use. Methods used by very large companies are very different than that of by medium or small companies.
  • Time available for testing – Ultimately, all the 50 testing types could be easily used. Time is a factor which often what limits us to using only those types that are most relevant for the project.
  • Resources available to the tester – Of course some testers may not have all the necessary resources to conduct any testing type. For example, if you are a software tester working for a very large software development firm. You are most likely to have expensive automated testing software that is not available to others.
  • Software Tester’s Education – There is a very certain learning curve for all types of software testing available. To use some of this software involved, a tester must learn how to use it.
  • Testing Budget – Money becomes a very important factor. Not just for the smaller companies and individual software developers but for large companies as well. 


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