Specify UTC timezone argument in datetime.now() and fix unit tests

[onkar]

While running unit tests locally using make test, I saw these failures:

=========================================================================================================== short test summary info ===========================================================================================================
FAILED tests/clickhouse/optimize/test_optimize.py::test_optimize_partitions_raises_exception_with_cutoff_time - Failed: DID NOT RAISE <class 'snuba.clickhouse.optimize.optimize_scheduler.OptimizedSchedulerTimeout'>
FAILED tests/clickhouse/optimize/test_optimize_scheduler.py::test_get_next_schedule[non parallel] - assert OptimizationSchedule(partitions_groups=[["(90,'2022-06-27')",\n                                         "(90,'2022-06-20')",\n   ...
FAILED tests/clickhouse/optimize/test_optimize_scheduler.py::test_get_next_schedule[parallel before final cutoff] - assert OptimizationSchedule(partitions_groups=[["(90,'2022-03-28')",\n                                         "(90,'202...
FAILED tests/clickhouse/optimize/test_optimize_scheduler.py::test_get_next_schedule_raises_exception - Failed: DID NOT RAISE <class 'snuba.clickhouse.optimize.optimize_scheduler.OptimizedSchedulerTimeout'>
FAILED tests/subscriptions/test_scheduler_consumer.py::test_tick_time_shift - AssertionError: assert Tick(partition=0, offsets=Interval(lower=0, upper=1), timestamps=Interval(lower=86400.0, upper=172800.0)) == Tick(partition=0, offsets=...
========================================================================== 5 failed, 2601 passed, 4 skipped, 2 deselected, 1 xfailed, 6 xpassed in 430.69s (0:07:10) ==========================================================================

The reason for failure is that some of these tests use time_machine's context manager, which expects the time in UTC. When these tests are run locally in PST, there is a difference of 7 hours that never triggers the cutoff time expiry.

>>> from datetime import datetime, timezone
>>> datetime.now()
datetime.datetime(2024, 9, 9, 11, 51, 15, 279890)
>>> datetime.now(timezone.utc)
datetime.datetime(2024, 9, 9, 18, 51, 26, 40580, tzinfo=datetime.timezone.utc)

The fix is to use datetime's timezone.utc instead of datetime.now(). Datetime also used to have datetime.utcnow() but it has been deprecated.

Note: I also fixed some non-test code, so I would appreciate reviews from experts in those areas.

[xurui-c]

I wonder if you can now remove the xfail here?

snuba/tests/clickhouse/optimize/test_optimize.py

Line 108 in 7370589

@pytest.mark.xfail(

[onkar]

I wonder if you can now remove the xfail here?

snuba/tests/clickhouse/optimize/test_optimize.py

Line 108 in 7370589

@pytest.mark.xfail(

Removed the xfail there and tests run successfully:

========================================================================= 2612 passed, 4 skipped, 2 deselected, 1 xfailed in 428.80s (0:07:08) ==========================================================================

[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
662	1	661	1

View the top 1 failed tests by shortest run time

tests.clickhouse.optimize.test_optimize.TestOptimize test_optimize[errors non-parallel]

Stack Traces | 0.853s run time

Traceback (most recent call last):
  File ".../clickhouse/optimize/test_optimize.py", line 213, in test_optimize
    assert partitions == []
AssertionError: assert [Part(name="(90,'1999-11-15')", date=datetime.datetime(1999, 11, 15, 0, 0), retention_days=90)] == []
  Left contains one more item: Part(name="(90,'1999-11-15')", date=datetime.datetime(1999, 11, 15, 0, 0), retention_days=90)
  Full diff:
  - []
  + [Part(name="(90,'1999-11-15')", date=datetime.datetime(1999, 11, 15, 0, 0), retention_days=90)]

To view individual test run time comparison to the main branch, go to the Test Analytics Dashboard

[onkar]

I wonder if you can now remove the xfail here?

snuba/tests/clickhouse/optimize/test_optimize.py

Line 108 in 7370589

@pytest.mark.xfail(

Removed the xfail there and tests run successfully:

========================================================================= 2612 passed, 4 skipped, 2 deselected, 1 xfailed in 428.80s (0:07:08) ==========================================================================

For some reason, the test_optimize.py tests fail in the CI but pass locally. I will take a look at this later. For now, I am going to keep the xfail as is and merge this PR.