What does integration testing an API involve?

Question

I'm diving into the world of API testing and coupled with that integration testing. It's made me think quite a lot about a few things:

1) Who would carry out integration tests? The dev or the tester?

2) What would integration tests entail, given that they are separate to end-to-end tests

3) Would we generally use mocks/stubs etc for integration.

Any advice would be great as this concept is causing me some confusion at the moment

Answer 1

Answering your questions

1. It doesn't really matter and depends on the test implementation and execution complexity, skills of dev and test people, their current tasks and tasks' priorities.
2. Integration tests are aimed to detect defects in components intercommunication. It's kinda technical aspect unlike E2E that involves more business-related actions. E2E tests also normally tend to cover a chain of components with some valuable business output.
3. If you have some components which you do not test the integration of, but which are vital for system run, you can use stub just to start up your application. However that makes no sense to test stub integration into your system.