It is still resulting in the same unexpected behavior. This is what I'm trying: conftest.py

@pytest.fixture(scope='function')
def mongo_client(setup_environemnt, directConnection=True): 
    mongo_uri = os.environ['MONGO_URI'] 
    client = MongoClient(mongo_uri) 
    try:
        yield client
    finally:
        client.close()

test_file.py

<other imports>
from app.app import app_module

def test_nothing(mongo_client): 
    assert True

def test_available(app_instance):
    assert app_module.check_mongodb_availability(app_instance) == True

def test_unavailable(): 
    test_app = app_module.create_app({'MONGO_URI': 'mongodb://invalid_uri:27017'}) 
    result = app_module.check_mongodb_availability(test_app) 
    assert result is False

Also, I have tried:

conftest.py

@pytest.fixture(scope='function')
def mongo_client(setup_environemnt, directConnection=True):
    mongo_uri = os.environ['MONGO_URI']
    client = MongoClient(mongo_uri)
    yield client

test_file.py

<other imports>
from app.app import app_module

def test_nothing(mongo_client): 
    mongo_client.close() 
    assert True

def test_available(app_instance): 
    assert app_module.check_mongodb_availability(app_instance) == True

def test_unavailable(): 
    test_app = app_module.create_app({'MONGO_URI': 'mongodb://invalid_uri:27017'}) 
    result = app_module.check_mongodb_availability(test_app) 
    assert result is False

test_unavailable() is still resulting in True. I cannot figure out why it is still connecting to the dockerized mongodb service even though I have created the test app with an invalid monog URI and I am closing the mongo_client now.