Test assumes system timezone is UTC

[szokeasaurusrex]

This test, added in #3546, assumes that the system time is UTC. The test fails otherwise because Python interprets the timestamp as if it is using the system's local timezone, but we assert that it is interpreted in UTC.

[BYK]

@szokeasaurusrex thanks for the report! Can you share which Python version this occurs on as I was not on UTC when I was writing this test and the point of the test was to make sure it worked on non-UTC timezone settings.

I'm assuming the culprit is us trying fromisoformat() first which defaults to local timezone when there's no timezone set.

[szokeasaurusrex]

@BYK I think it was 3.12