Integration Testing

Integration testing is a software testing method that validates how different software modules work together as a group. Integration testing occurs after unit testing and before system testing. The goal is to test the interactions between integrated components or systems to find bugs and ensure that the integrated product functions as expected.

During integration testing, individual software modules are combined and tested as a group. For example, in a web application, the user interface, backend database, APIs, and other components are integrated together and verification tests are run to ensure they communicate properly. Test cases focus on testing interfaces between components and verifying the flow of data between them. Example test cases could include testing login functionality from the UI through the backend, testing database reads/writes from an API call, or testing a payment transaction across the full software stack. By testing integrated components, issues like incompatible interfaces, missing operations, and incorrect data flow can be detected and fixed early. Effective integration testing requires knowledge of the whole system architecture to methodically connect components and verify correct interoperation.