How to test other thread that access database

It seem that the database used by django during tests isn't shared with other thread

For example:

inside a TestCase class :

def my_test(self):
    print(MyModel.objects.all())
    my_function()

inside my class :

def worker():
    print(MyModel.objects.all())

def my_function():
    thread = Thread(target=worker)
    thread.start()

Console result :

[<MyModel object>, <MyModel object>, <MyModel object> ... ]
[]

So We get the first call, but as soon as we are inside another thread, it doesn't use the test db anymore.

I looked at : Django: using same test database in a separate thread and tried to use the same db for "NAME" and "TEST_NAME" but it doesn't work for me

What could I do to test my threads even if they are accessing db ?