Know All About System Integration Testing
System Integration Testing (SIT) is the overall testing of the whole system, which is composed of many sub-systems. The main objective of SIT is to ensure that all software module dependencies function properly and the data integrity is preserved between distinct modules of the whole system.
System integration testing is a type of software testing which is performed in an integrated hardware and software atmosphere to comprehend the behaviour of the complete system. It is a testing which is performed to analyse the system’s complete compliance with its specified needs.
Usually, system integration testing is done in order to verify the interactions which happen between modules of software.
System integration testing also verifies a software’s coexistence with others and usually tests the interface between different modules of software application. Under this, modules are tested first individually and then they are clubbed to form a system.
Why should you do system integration testing?
System integration testing is useful in detecting bugs at an early stage. Once found, software is sent back to the development team. It helps in saving time and cost of rectifying it at a later stage.
With the help of system integration testing, it is feasible to get an early opinion on the module acceptability in the system.
It helps in exposing those bugs which can take place during the interaction of integrated components.
Various modules are there in a system and it is daunting to do unit testing of all the modules individually. Moreover, even if each unit is tested individually, the chances are high that it can fail to perform when integrated as a whole. Therefore, there is a need for system integration testing to uncover and fix bugs before sending them to the user.
Usually, most of the testing life cycles depend on end-to-end testing. Though, it is crucial to have end-to-end testing; it is also important to have system integration testing in the software testing life span.
Let’s have a look at different approaches for doing system integration testing:
- Top Down Approach: It is an incremental approach where testing starts at the topmost application module. At a lower level, module functionality is simulated by using stubs. Once each test is completed, stubs are replaced by the real module. It is continuously performed until the entire system is tested.
- Bottom-Up Approach: In this, the lowest module levels are first brought together in order to form clusters. The modules are integrated from bottom to top.
- Big Bang Approach: All modules are not integrated unless they are ready. Once they are ready, they are integrated and executed to know whether all integrated modules are working or not. Under this approach, it is difficult to know the failure cause. Also the chances are high that critical bugs may arise during the production environment. Such kind of approach can be adopted only when it is required to do integration testing only for once.
System testing Vs. System integration testing
- Under integration testing, individual software modules are combined and then tested as a group, while system testing is a testing which is performed on an integrated and complete system to assess the system’s compliance with its divergent requirements.
- System integration testing involves testing interface between different modules- top down, bottom up and big bang. However, system testing means testing different business scenarios.
- While system testing is done at a final level, integration testing is done at each stage of module binding.
- System testing is a high level testing, whereas integration testing is mainly low level testing. In short, system testing starts at the completion of integration testing, not vice versa.
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