sdks/python/apache_beam/typehints/trivial_inference_test_py3.py

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"""Tests for apache_beam.typehints.trivial_inference that use Python 3 syntax.
"""

from __future__ import absolute_import

import unittest

from apache_beam.typehints import trivial_inference
from apache_beam.typehints import typehints


class TrivialInferenceTest(unittest.TestCase):

  def assertReturnType(self, expected, f, inputs=(), depth=5):
    self.assertEqual(
        expected,
        trivial_inference.infer_return_type(f, inputs, debug=True, depth=depth))

  def testBuildListUnpack(self):
    # Lambda uses BUILD_LIST_UNPACK opcode in Python 3.
    self.assertReturnType(typehints.List[int],
                          lambda _list: [*_list, *_list, *_list],
                          [typehints.List[int]])

  def testBuildTupleUnpack(self):
    # Lambda uses BUILD_TUPLE_UNPACK opcode in Python 3.
    self.assertReturnType(typehints.Tuple[int, str, str],
                          lambda _list1, _list2: (*_list1, *_list2, *_list2),
                          [typehints.List[int], typehints.List[str]])


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