Software Development

What is Integration Testing?

Quick answer

Testing that checks whether different parts of a software system, such as services, databases, and APIs, work correctly together.

Integration Testing, explained

Unit tests check small pieces of code in isolation. Integration tests go a level higher and verify that those pieces cooperate as expected, for example that an application can save a record to a real database, call a payment provider's test environment, or pass data between two services.

Consider a food delivery app. A unit test might confirm that a function calculates the delivery fee correctly, while an integration test would place an order through the API and check that the order is stored, the restaurant receives it, and a confirmation message is queued. Integration tests catch problems with configuration, data formats, and network calls that unit tests miss. They are slower and harder to maintain, so teams usually keep fewer of them than unit tests.

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