As the name implies, integration testing is the process of testing individual components to see how well they perform conjoined. These components are combined to better understand multiple modules operating as a single unit. There are various types of integration testing, such as Big Bang Testing, Incremental Testing, Top-Down Testing and Bottom-Up Testing. Dan Packer has brilliantly explained these types in Integration Testing in an Enterprise DevOps Environment.
We have identified 4 key reasons as to why integration testing is essential, and why you should employ it in your organisation:
- Enables Better Integration of Modules
- Prevents Changes in Data during Module Transfers
- Enables Effective Third-Party Testing
- Overcomes Problems of Manual Testing
1. Enables Better Integration of Modules
Whenever companies hire engineers to develop an application, it is usually broken down into multiple modules. Each module is handled by a separate developer, and different code and logic may be used for each module, even if the same language is applied.
There is always a possibility that modules developed by different developers may not sync when assembled. By deploying integration testing, such problems can be avoided.
2. Prevents Changes in Data during Module Transfers
It is quite common for data changes to occur when transferred from one module to another; the programmer might have designed the module differently from what is delivered. Consequently, this causes issues in integration with other modules because of such modifications.
If your company is facing this problem, integration testing can help by testing the compatibility of each module early-on to help make changes accordingly.
3. Enables Effective Third-Party Testing
Application Programming Interface, or API, consists of clear instructions on communication between different components. Having an exceptional API is crucial for businesses as it makes developing computer programs easier. Modules usually interact with these APIs or third-party tools to incorporate a user-friendly outlook.
However, as we discussed above, data usually changes while transferring. Therefore, it is important to check whatever received by the API is accurate and the response meets expectations. For this purpose, integration testing is highly valuable.
4. Overcomes Problems of Manual Testing
A developer typically uses the following approach for manual testing:
- Identifies the problem
- Brainstorms ways to solve the problem
- Selects the most appropriate course of action to fix the problem
- Manually checks whether the problem has been resolved
- In case of remaining issues, repeats the steps
The problem with manual testing is that you observe one facet of the system at a time. For this reason, it is important for developers to employ integration testing in order to avoid faults in the end-product.
We have identified 4 key reasons pertaining to the importance of integration testing:
- Different code may be used by developers, hence integration is necessary to bring uniformity in the end-product
- Data may change while transferring from one point to another
- When data interacts with APIs/third-parties, it may diverge from what might have originally been sent
- Manual testing is not as useful as integration testing
Moreover, developers predict that integration testing will not only become mainstream but also become a necessity in the near future.
If you are still on the fence, here is an interesting thread on Quora regarding the future of software testing.