While Integration testing has multiple approaches that you can adopt as per your testing needs, two of the popular ones are Top-down and Bottom-up. In the top down integration testing approach, we first test the data records, then the data records integrated with Profile Page, and then all three. Conventionally, one may find the top-down testing usage of stubs only applicable when the module is still under development. However, stubs are very important in top down integration testing, even if the developers have built the module. If we start using the developed module, we may not be able to identify whether the bug is in the sub-module or the one we are testing.
- This testing tool works for both unit and integrating testing projects, significantly reducing costs and time by automating much of the testing process.
- Integration testing is usually done simultaneously with development.
- But these delay testing of the ultimate functional units of a system until significant design is complete.
- However, stubs are very important in top down integration testing, even if the developers have built the module.
- This technique follows the control flow or architectural structure to test it from top to bottom.
Although it might be hard to imagine, if any of the pieces are left to be under developed and left incomplete. These terms (stub & driver) come into the picture while doing Integration Testing. While working on integration, sometimes we face a situation where some of the functionalities are still under development. So the functionalities which are under development will be replaced with some dummy programs. The purpose of Bottom-up Integration testing is to uncover crucial issues like input or output data usage, which are usually performed by sub-modules early in the testing stage.
Although all these types have their use cases and advantages, this blog focuses on Top-down and Bottom-up approaches and the differences between them. As the name suggests, hybrid or mixed Integration testing combines Top-down and Bottom-up to achieve the advantages of both types. However, you must have a thorough knowledge of Integration testing and its requirements before you jump to understanding its different approaches. Deliver unparalleled digital experience with our Next-Gen, AI-powered testing cloud platform. Ensure exceptional user experience across all devices and browsers. And this sequence can be continued if there exists another level of modules.
Ready to start your integration journey?
Later, the programming team looks at the requirements of each of those functions and the process is repeated. These compartmentalized subroutines eventually will perform actions so simple they can be easily and concisely coded. When all the various subroutines have been coded the program is ready for testing.
The most significant advantage of executing this approach is its user-friendliness which provides high deployment coverage in software development. Bottom-up Integration Testing is a strategy in which the lower level modules are tested first. These tested modules are then further used to facilitate the testing of higher level modules.
White Box Techniques
Since top down integration testing (also referred to simply as top down testing) is a method to perform incremental testing, it is advantageous for us to explore a few more points in this high-level approach. For example, Figure shows the mainline logic for Customer Maintenance. The mainline of logic is important because it will be executed every time a maintenance request is performed.
This strategy often resembles a “seed” model, by which the beginnings are small, but eventually grow in complexity and completeness. Object-oriented programming (OOP) is a paradigm that uses “objects” to design applications and computer programs. Sandwich integration testing, also know as hybrid integration testing, is a method that combines the advantages of both top-down and bottom-up strategies. Sandwich testing involves testing high-level modules and working down, while simultaneously performing tests on low-level modules and working up. Sandwich Testing is a strategy in which top level modules are tested with lower level modules at the same time lower modules are integrated with top modules and tested as a system. It is a combination of Top-down and Bottom-up approaches therefore it is called Hybrid Integration Testing.
In this way, all the modules are integrated and tested simultaneously. This approach connects two or more components together that are logically compatible. As the test progresses more components are added to understand and test all the component’s functionality successfully. This approach can be further divided into a top-down approach, a bottom-up approach and a sandwich approach. Big Bang testing is one of the testing approaches that could be used. When all the components have been developed and tested individually they are integrated once and tested together.
For large applications, big bang integration testing can compromise the quality of an application by overlooking finer aspects. Top-down testing can also be used easily with
prototyping and iterative development. Prototyping
is iterative and follows the same logic for adding
code as top-down testing.
This method is used in the analysis of both natural languages and computer languages, as in a compiler. Mail us on h[email protected], to get more information about given services. A writer for 4+ years with QA and Engineering background, I have always liked to blend creativity with technology. Although my experience plays an important role in making every article ‘my own piece of work,’ I believe writing is a never-ending learning process where I am still a student. Besides creating content, I try to read every book there ever existed and travel to places that are within reach (for now).