They verify interactions between system components, catching errors unit tests miss.
Integration tests ensure that different parts of an application work together as expected. Though resource-intensive, they are crucial for complex systems like an e-commerce platform, where the checkout process might involve multiple services such as inventory, payment, and shipping. By running integration tests, you verify that these services interact correctly, providing end-to-end assurance.
Additional Notes
Why might integration tests be worth the cost in complex applications?