How to read env vars from settings in django unittest?

I am new to unittesting. I want to read some env vars in django unittests, but I am having some troubles when trying to read the env var from django.conf.settings, but I can read the env var using os.environ.get(). How can I access the current env var from django.conf.settings?

The test code looks like the following:

from unittest.mock import patch

    
    def test_functionality_in_non_production_environments(self):
        with patch.dict('os.environ', {
            'ENVIRONMENT': 'local',
            'ENV_VALUE': 'test_env_value',
        }):
            from django.conf import settings
            print(settings.ENV_VALUE)           # --> DOES NOT PRINT 'test_env_value'
            print(os.environ.get('ENV_VALUE'))  # --> PRINTS 'test_env_value'

In settings.py:

ENV_VALUE = os.environ.get('ENV_VALUE', 'some other value')

I am trying to test the correct behaviour of the code depending on the env var.

In some parts of the code there is some logic like:

if settings.ENV_VALUE and setting.ENVIRONMENT == 'local':
    # do some stuff

You can override django settings using override_settings decorator:

from django.test import TestCase, override_settings

@override_settings(ENV_VALUE='test_env_value', ENVIRONMENT='local')
def test_functionality_in_non_production_environments(self):
    from django.conf import settings
    print(settings.ENV_VALUE)           
    print(os.environ.get('ENV_VALUE'))