Fix tests that were intermittently failing in CI

[AlanGreene]

Changes

These tests have been failing intermittently in CI for about a year now but until now had been unable to reproduce locally. For some unknown reason (suspect dependency updates) they became consistently reproducible locally this week, but were consistently passing in CI :shrug:

Ensure all expected API calls are mocked for the error cases in the affected tests so that they behave predictably.

/kind misc

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