During implementation, a module can work on its own while its interactions with other modules still need checking. An integration test combines software modules or components and tests them as a group to see whether they work together to meet system requirements. section 10.1.4 section 12.2.2
Choose the test by the scope of the question:
- Does one small unit, such as a function or method, work? Use a unit test. section 12.2.2
- Do combined components interact correctly? Use an integration test. section 12.2.2
- Does the entire application behave as expected in a production-like scenario? Use an end-to-end test. section 12.2.2
The test automation pyramid helps the engineering team produce high-quality software. It works at three levels: unit testing (base step), integration testing (middle step)m and end-to-end testing (top).
The test automation pyramid places integration testing between unit testing and end-to-end testing. section 12.2.2
Track test coverage to spot gaps during development, but do not treat coverage as a guarantee that the code is bug-free. When reviewing a change, ask which component interactions its integration tests check. section 12.2.2 section 10.1.4
