These aren't unit tests, they are integration tests (API calls to an external system). Integration tests have had multiple assertions forever (look at how Cypre

These aren't unit tests, they are integration tests (API calls to an external system). Integration tests have had multiple assertions forever (look at how Cypress works where each test step is an assertion), the idea of single assertions are for unit tests. The issue with multiple assertions for unit tests is that they hide errors by failing early extending the time to fix (fail at Assert 1, fix, re-run, fail at Assert 2, fix...). If you want multiple assertions you should have a single assertion that can report multiple issues by returning an array of error strings or something. The speed increase of multiple assertions vs multiple tests is usually tiny, but if you do have a long unit test then that's basically the only reason I can think of to use multiple assertions.