database connection isn't set to UTC - Django getting timestamp

Question

Set-up

I'm trying to run unit tests in Django.

pipenv run python manage.py test test_module.tests.test_application.ExampleTest

I'm getting the following error:

Traceback (most recent call last):
  File "C:\Users\Dom_W\Documents\Development\Projects\project_test\data_load_api_functions\tests\test_deepcrawl_api.py", line 210, in setUp
    print(list(User.objects.all()))
  File "C:\Users\Dom_W\.virtualenvs\example-project-n37Jnk2\lib\site-packages\django\db\models\query.py", line 274, in __iter__
    self._fetch_all()
  File "C:\Users\Dom_W\.virtualenvs\example-project-n37Jnk2\lib\site-packages\django\db\models\query.py", line 1242, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File "C:\Users\Dom_W\.virtualenvs\example-project-n37Jnk2\lib\site-packages\django\db\models\query.py", line 55, in __iter__
    results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
  File "C:\Users\Dom_W\.virtualenvs\example-project-n37Jnk2\lib\site-packages\django\db\models\sql\compiler.py", line 1130, in execute_sql
    return list(result)
  File "C:\Users\Dom_W\.virtualenvs\example-project-n37Jnk2\lib\site-packages\django\db\models\sql\compiler.py", line 1509, in cursor_iter
    for rows in iter((lambda: cursor.fetchmany(itersize)), sentinel):
  File "C:\Users\Dom_W\.virtualenvs\example-project-n37Jnk2\lib\site-packages\django\db\models\sql\compiler.py", line 1509, in <lambda>
    for rows in iter((lambda: cursor.fetchmany(itersize)), sentinel):
  File "C:\Users\Dom_W\.virtualenvs\example-project-n37Jnk2\lib\site-packages\django\db\utils.py", line 96, in inner
    return func(*args, **kwargs)
  File "C:\Users\Dom_W\.virtualenvs\example-project-n37Jnk2\lib\site-packages\django\db\backends\postgresql\utils.py", line 9, in utc_tzinfo_factory
    raise AssertionError("database connection isn't set to UTC")
AssertionError: database connection isn't set to UTC

I think it might've started because of the switch to BST, but now despite forcing timezone I can't get Django to recognise it.

What I've tried

I set the default Postgres timezone to UTC in postgresql.conf

That did nothing so I inspected the function which is responsible:

def utc_tzinfo_factory(offset):
    if offset != 0:
        raise AssertionError("database connection isn't set to UTC")
    return utc

And discovered it's being given a datetime.timedelta with a value of 0:00:00 which then causes this line to fail:

if offset != 0:

Why isn't it receiving an integer? And how on earth can I fix this?

If I comment out the line, then it all just works fine... But otherwise there is some sort of timezone mismatch.

Env

• Windows 10
• Django: 2.2
• Postgresql: 13