[airflow] awsHook

https://programtalk.com/python-examples/airflow.contrib.hooks.aws_hook.AwsHook/

 @unittest.skipIf(mock_emr is None, 'mock_emr package not present')
    @mock_emr
    def test_get_client_type_returns_a_boto3_client_of_the_requested_type(self):
        client = boto3.client('emr', region_name='us-east-1')
        if len(client.list_clusters()['Clusters']):
            raise ValueError('AWS not properly mocked')

        hook = AwsHook(aws_conn_id='aws_default')
        client_from_hook = hook.get_client_type('emr')

        self.assertEqual(client_from_hook.list_clusters()['Clusters'], [])