Tortoise.get_connection in pytest test raises a KeyError

Describe the bug
My project uses some raw SQL. For this, I use Tortoise.get_connection() to get a DB connection. This fails when I run unit tests with pytest with a KeyError.

To Reproduce
test_connection.py:

from tortoise import Tortoise
async def test_get_connection():
    c = Tortoise.get_connection('default')

$ pytest test_connection.py

Expected behavior
The test should succeed without an exception. I also tried 'models' and 'test' for the connection name.

Additional context
This seems to be caused by tortoise.contrib.test.initializer() which contains this code:

_CONNECTIONS = Tortoise._connections.copy()
_CONN_MAP = current_transaction_map.copy()
Tortoise.apps = {}
Tortoise._connections = {} 

Start with test_connection.py and the tortoise.contrib.test.initializer() entry point, then trace how Tortoise._connections is cleared before Tortoise.get_connection('default') runs. Reproduce the KeyError with pytest and verify that the connection lookup succeeds without an exception for the configured connection name.