Do I need to use mocks?

I have the function which handles a specific bot event from Slack. Generally speaking, user clicks a button then my server receives and handles payload of this button.

The question is how should I test it? Do I need to mock make_admin and build_admins_message and check that they were called or I need to test real implementations? For example, I can retrieve the user from the database and check that it is actually an admin and also check that build_admins_message returns a dictionary that I expect to receive.

@slack_interactions.on('admin_add')
def handle_admin_add(payload):
    team_id = payload['team']['id']
    user_id = payload['user']['id']
    action_value = payload['actions'][0]['selected_options'][0]['value']

    user = SlackUser.objects.find_by_ids(team_id, action_value)

    if user and not user.is_bot:
        user.make_admin()

    return build_admins_message(team_id, user_id)

Currently my tests look like this:

class TestAdminAddHandler(TestCase):
    def setUp(self):
        team = SlackTeam.objects.create(team_id='TEAMID')
        SlackUser.objects.create(team=team, user_id='USERID')
        SlackUser.objects.create(team=team, user_id='BOTID', is_bot=True)
        SlackUser.objects.create(
            team=team, user_id='ADMINID', is_bot_admin=True)

    def tearDown(self):
        SlackUser.objects.all().delete()
        SlackTeam.objects.all().delete()

    def test_wrong_callback(self):
        payload = {'callback_id': 'wrong_callback'}
        message = handle_admin_add(payload)
        self.assertIsNone(message)

    def test_has_no_user(self):
        payload = {
            'callback_id': 'admin_add',
            'team': {'id': 'TEAMID'},
            'user': {'id': 'ADMINID'},
            'actions': [{
                'selected_options': [{'value': 'BADID'}]
            }]
        }

        message = handle_admin_add(payload)

        user = SlackUser.objects.get(user_id='USERID')
        self.assertFalse(user.is_bot_admin)

        for att in message['attachments']:
            self.assertNotIn('BADID', att.get('title', ''))

    def test_user_is_bot(self):
        payload = {
            'callback_id': 'admin_add',
            'team': {'id': 'TEAMID'},
            'user': {'id': 'ADMINID'},
            'actions': [{
                'selected_options': [{'value': 'BOTID'}]
            }]
        }

        message = handle_admin_add(payload)
        user = SlackUser.objects.get(user_id='BOTID')
        self.assertFalse(user.is_bot_admin)

        for att in message['attachments']:
            self.assertNotIn('BOTID', att.get('title', ''))

    def test_add_admin(self):
        payload = {
            'callback_id': 'admin_add',
            'team': {'id': 'TEAMID'},
            'user': {'id': 'ADMINID'},
            'actions': [{
                'selected_options': [{'value': 'USERID'}]
            }]
        }

        message = handle_admin_add(payload)

        user = SlackUser.objects.filter(user_id='USERID').first()
        self.assertTrue(user.is_bot_admin)

        user_in_list = False
        for att in message['attachments']:
            if 'USERID' in att.get('title', ''):
                user_in_list = True

        self.assertTrue(user_in_list)