'Fetching application settings for the wrong platform raises ImproperlyConfigured.'

def test_platform_invalid_setting(self):

    application_id = 'my_fcm_app'
    PUSH_SETTINGS = {'APPLICATIONS': {application_id: {'PLATFORM': 'FCM', 'API_KEY': '[my_api_key]'}}}
    manager = AppConfig(PUSH_SETTINGS)
    with self.assertRaises(ImproperlyConfigured) as ic:
        manager._get_application_settings(application_id, 'APNS', 'CERTIFICATE')
    self.assertEqual(str(ic.exception), "Application    'my_fcm_app'    (FCM)    does    not    support    the    setting    'CERTIFICATE'.")
