sdks/python/apache_beam/examples/wordcount_minimal_test.py

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"""Test for the minimal wordcount example."""

from __future__ import absolute_import

import collections
import logging
import re
import tempfile
import unittest

from apache_beam.examples import wordcount_minimal
from apache_beam.testing.util import open_shards


class WordCountMinimalTest(unittest.TestCase):
  """Unit test for wordcount_minimal example with direct runner."""

  SAMPLE_TEXT = 'a b c a b a\n aa bb cc aa bb aa'

  def create_temp_file(self, contents):
    with tempfile.NamedTemporaryFile(delete=False) as f:
      f.write(contents.encode('utf-8'))
      return f.name

  def test_basics(self):
    temp_path = self.create_temp_file(self.SAMPLE_TEXT)
    expected_words = collections.defaultdict(int)
    for word in re.findall(r'\w+', self.SAMPLE_TEXT):
      expected_words[word] += 1
    wordcount_minimal.run(
        ['--input=%s*' % temp_path,
         '--output=%s.result' % temp_path],
        save_main_session=False)
    # Parse result file and compare.
    results = []
    with open_shards(temp_path + '.result-*-of-*') as result_file:
      for line in result_file:
        match = re.search(r'([a-z]+): ([0-9]+)', line)
        if match is not None:
          results.append((match.group(1), int(match.group(2))))
    self.assertEqual(sorted(results), sorted(expected_words.items()))


if __name__ == '__main__':
  logging.getLogger().setLevel(logging.INFO)
  unittest.main()