# Copyright 2018 Google LLC

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

# https://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

"""Utilities for unit testing DAGs."""

# [START composer_dag_unit_testing]

from airflow import models

def assert_has_valid_dag(module):

"""Assert that a module contains a valid DAG."""

no_dag_found = True

for dag in vars(module).values():

if isinstance(dag, models.DAG):

no_dag_found = False

dag.test_cycle() # Throws if a task cycle is found.

if no_dag_found:

raise AssertionError('module does not contain a valid DAG')

# [END composer_dag_unit_testing]