I avoid writing automated tests that hit an external API - especially one out of my control - because I don't want my CI runs to ever fail because someone else's service wasn't responding. I want CI to be a completely closed box, such that any failures mean there's a bug in my code.

If I want to test external APIs I'll do that in a separate set of integration tests which are run as part of a separate system, not as part of my CI for every code commit to my repo.

I mostly use Python, and the APIs I talk to are mostly accessed via the requests or httpx libraries - both of which have excellent libraries for productive mocking:

- https://requests-mock.readthedocs.io/en/latest/pytest.html

- https://github.com/Colin-b/pytest_httpx