Here's a breakdown of what IST testing involves:
* Focus: Verifying the interfaces and interactions between integrated modules. It doesn't focus on individual units (that's unit testing), nor the entire system's functionality (that's system testing).
* Approach: Modules are combined incrementally, and testing occurs at each integration step. Common approaches include:
* Big Bang Integration: All modules are integrated at once and tested as a whole. This is riskier but can be faster if the modules are well-tested individually.
* Top-Down Integration: Starts with the top-level module and integrates lower-level modules gradually.
* Bottom-Up Integration: Starts with the lowest-level modules and integrates upwards.
* Sandwich Integration (Hybrid): A combination of top-down and bottom-up integration.
* Objectives:
* To detect defects in the interfaces between modules.
* To ensure that data flows correctly between modules.
* To verify that the integrated modules meet the specified requirements.
* To identify performance bottlenecks in the integration.
* Techniques: Various testing techniques can be used, including functional testing, performance testing, and security testing, tailored to the integrated components.
In short, IST testing is a crucial step in software development, ensuring that the different parts of a system work harmoniously before the entire system undergoes more comprehensive testing. It helps to catch integration-related issues early, preventing costly fixes later in the development lifecycle.