sdks/python/apache_beam/examples/snippets/transforms/aggregation/sample_test.py

# coding=utf-8
#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You 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
#
#    http://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.
#

from __future__ import absolute_import
from __future__ import print_function

import unittest

import mock

from apache_beam.examples.snippets.util import assert_matches_stdout
from apache_beam.testing.test_pipeline import TestPipeline

from . import sample


def check_sample(actual):
  expected = '''[START sample]
['🥕 Carrot', '🍆 Eggplant', '🍅 Tomato']
[END sample]'''.splitlines()[1:-1]
  # The sampled elements are non-deterministic, so check the sample size.
  assert_matches_stdout(actual, expected, lambda elements: len(elements))


def check_samples_per_key(actual):
  expected = '''[START samples_per_key]
('spring', ['🍓', '🥕', '🍆'])
('summer', ['🥕', '🍅', '🌽'])
('fall', ['🥕', '🍅'])
('winter', ['🍆'])
[END samples_per_key]'''.splitlines()[1:-1]
  # The sampled elements are non-deterministic, so check the sample size.
  assert_matches_stdout(actual, expected, lambda pair: (pair[0], len(pair[1])))


@mock.patch('apache_beam.Pipeline', TestPipeline)
@mock.patch(
    'apache_beam.examples.snippets.transforms.aggregation.sample.print', str)
class SampleTest(unittest.TestCase):
  def test_sample_fixed_size_globally(self):
    sample.sample_fixed_size_globally(check_sample)

  def test_sample_fixed_size_per_key(self):
    sample.sample_fixed_size_per_key(check_samples_per_key)


if __name__ == '__main__':
  unittest.main()