Service(airflow_service).is_running fails testing airflow-scheduler

[jnogol]

Due to the scheduler is not constantly up & running and reboots itself every five seconds, Service(airflow_service).is_running assertion fails depending on the moment it is checked.

To fix this, we are going to add the @retry decorator from retrying Python module and make test_airflow_services check if the services are running during a maximum of 5 seconds:

from retrying import retry

@retry(stop_max_delay=5000)
def test_airflow_services(Service, AnsibleDefaults):
    airflow_services = AnsibleDefaults["airflow_services"]

    for airflow_service in airflow_services:
        if airflow_services[airflow_service]["enabled"]:
            assert Service(airflow_service).is_enabled
            assert Service(airflow_service).is_running