November 30, 2016

7 Things About Software System Testing You Should Know

According to ISTQB “System Testing is a level of software testing where a complete and integrated software is tested. The purpose of software system testing is to evaluate the system’s compliance with the specified requirements.” In this post you will find the 7 most essential things you should know about Software System Testing.

1) Software System Testing is performed on the Integrated Product

Initially, the software product is divided into smaller components and modules. These components are developed independently so that the development of several components can continue in parallel. These components are tested and fixed individually.

Near completion, these components, modules or sub-system are integrated together to handover the client an integrated product.

Note that several issues can arise when these separately developed components and modules are combined – although they might have been fully tested and found good for the release. Hence, software system testing is the last chance to identify any defects and issues before the system goes live.

Replicate the production environment as your test environment and perform thorough system testing.

2) Complete Understanding of Work, Data and Process Dependencies is Required

It might be possible that you enter some data from UI form at one screen, which needs to be processed and displayed in another screen, component or module. For example, if you are adding a new vehicle in the fleet; it needs to be displayed in the report of ‘Available Vehicles’. These kinds of scenarios are the crux of software system testing i.e. how successfully the system behaves as a whole.

For big and complex projects, you shall make a clear chart of dependencies. You need to clearly understand the data flow, workflow and process dependencies. This understanding is essential to identify which functionalities and data should be necessarily checked for software system integration. These diagrams can be time-consuming and may require some effort, but the consequence of not doing it might result in overlooking loopholes in the system.

3) User Stories are the Guide for Software System Testing

Since system testing is focused at the behaviour of whole system, it is recommended that you use user stories as basis of test cases for software system testing. User stories are the requirements of software system captured from the viewpoint of end user. They help to focus on the required feature, instead of focusing on how the solution is implemented. This means that user stories can be key if you want to perform end to end testing from user’s viewpoint. It is the responsibility of business analyst to make user stories which are testable.

Another important tip is to make sure that you create users for all roles that are present in the system. It often happens that testers create users for main roles only and forget the others, however it is essential that you create users for all roles and perform at least one complete cycle of the possible workflows according to the permissions for the particular role. Also, remember to note down the errors and warning messages that appear while interacting with the system. These errors should be proper messages understandable by the users.

4) Use Good Test Data

You cannot be completely confident about the quality of testing unless you have used good test data – instead of entering ‘Test’ in every text field and ‘123…9’ in every numeric field, enter the real-world strings and numeric values. You need to keep in mind a few things while preparing test data.

First, your test data should be realistic i.e. you should enter data which the end user is expected to enter. By identifying data in and data out, you can confidently define test success or failure. Second, you should have enough data and number of records in the system to evaluate how the system will perform under different loads of data in the database. You might even create scripts for entering test data or use some data generation tool to simplify and expedite the process.

5) Know How to do Software System Testing

The first step of performing software system testing is to create its test plan. After the test plan is drawn up, system test cases are created and required test data is generated. Software system testing is performed when the application meets the entry criteria. The entry criteria include the following:

  • All modules and components have been integrated
  • Unit testing and integration testing is completed
  • All required features and functionalities have been developed
  • Software test environment resembling to production environment have been set up

Once the application meets the entry criteria, test cases are executed, bugs are raised, issues are fixed and retested. When all the issues have been fixed and verified by the QA team, the release is given green signal and handed over to the client.

6) System Testing is Different from System Integration Testing

As a new tester, you might confuse system integration testing with the software system testing. System testing is performed at the whole system, whereas system integration testing is performed when modules are integrated to see whether they are returning the expected outcome. System testing is a high-level testing and does not require any knowledge of the code or internal structure. On the contrary, system integration testing requires the knowledge of two interfaces and their interaction.

The test cases in system testing are focused on real world scenarios, whereas the integration test cases are focused on how two or more modules will interact. System testing comprises of several other testing types including functionality, performance, stress, load, and integration testing. System integration testing can be performed by using different approaches such as top-down, bottom-up, and hybrid approach. Most importantly, system integration testing is performed to find the bugs in individual modules while system testing is performed to find the bugs in the whole integrated system.

7) Challenges in System Testing for a New Tester

As a new tester, you might face several challenges when performing software system testing for the first time.

The first challenge is to gain thorough understanding of the complete system. You might have knowledge of one or two modules of the system, but this is insufficient to perform system testing. In addition to it, you need to fully understand the data flows and workflows. This challenge can be overcome by skimming the requirements specifications documents. If the system is too big and complex, you can take help from the flowcharts and workflow diagrams. An understanding of how different modules of the system interact with each other provides an edge in the intelligent creation of test cases.

The second challenge is to understand the different roles in the system and their interaction with the system. Understanding the viewpoints of users is required to create system test cases. To overcome this challenge, go through the user stories, use cases and activity diagrams.

Third, you might face some trouble in generating large volumes of realistic test data. You can insert large volumes of required data in the database by creating either database scripts or by using data generator tools.

The fourth challenge is to have a firm grip on the various testing types that comprise the system testing. These include the functional and non-functional testing types. You can take help from automated testing tools to speed up the process.


Software system testing is performed at the complete system to verify that it meets the user requirements. The major focus of software system testing is to make sure that system works perfectly well for end to end scenarios. In this article, we discussed some important things that every new software tester must know about software system testing. We also looked at a few challenges that you might face while performing system testing as a new tester, and how you can overcome those challenges.

What is your experience with software system testing? Share your advice in the comments section below to help the new testers in their task of software system testing.

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