what is integration test

Integration testing is a type of software testing that focuses on verifying the interactions and data exchange between different components or modules of a software application. It is conducted after unit testing, where the functional correctness of the smallest piece of code, or unit, is tested. The aim of integration testing is to test the interfaces between the modules and expose any defects that may arise when these components are integrated and need to interact with each other. Integration testing involves integrating the various modules of an application and then testing their behavior as a combined, or integrated, unit. It takes as its input modules that have been unit tested, groups them in larger aggregates, applies tests defined in an integration test plan to those aggregates, and delivers as its output the integrated system ready for system testing. Some different types of integration testing are big-bang, mixed (sandwich), risky-hardest, top-down, and bottom-up. Integration testing is an essential part of software testing as it validates if the modules can communicate well with each other, which is something that can’t be tested with unit testing.