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"""Unit tests for coders that must be consistent across all Beam SDKs.
"""
from __future__ import absolute_import
from __future__ import print_function

import json
import logging
import math
import os.path
import sys
import unittest
from builtins import map

import yaml

from apache_beam.coders import coder_impl
from apache_beam.portability.api import beam_runner_api_pb2
from apache_beam.runners import pipeline_context
from apache_beam.transforms import window
from apache_beam.transforms.window import IntervalWindow
from apache_beam.utils import windowed_value
from apache_beam.utils.timestamp import Timestamp

STANDARD_CODERS_YAML = os.path.normpath(os.path.join(
    os.path.dirname(__file__), '../portability/api/standard_coders.yaml'))


def _load_test_cases(test_yaml):
  """Load test data from yaml file and return an iterable of test cases.

  See ``standard_coders.yaml`` for more details.
  """
  if not os.path.exists(test_yaml):
    raise ValueError('Could not find the test spec: %s' % test_yaml)
  with open(test_yaml, 'rb') as coder_spec:
    for ix, spec in enumerate(yaml.load_all(coder_spec)):
      spec['index'] = ix
      name = spec.get('name', spec['coder']['urn'].split(':')[-2])
      yield [name, spec]


def parse_float(s):
  x = float(s)
  if math.isnan(x):
    # In Windows, float('NaN') has opposite sign from other platforms.
    # For the purpose of this test, we just need consistency.
    x = abs(x)
  return x


class StandardCodersTest(unittest.TestCase):

  _urn_to_json_value_parser = {
      'beam:coder:bytes:v1': lambda x: x.encode('utf-8'),
      'beam:coder:bool:v1': lambda x: x,
      'beam:coder:string_utf8:v1': lambda x: x,
      'beam:coder:varint:v1': lambda x: x,
      'beam:coder:kv:v1':
          lambda x, key_parser, value_parser: (key_parser(x['key']),
                                               value_parser(x['value'])),
      'beam:coder:interval_window:v1':
          lambda x: IntervalWindow(
              start=Timestamp(micros=(x['end'] - x['span']) * 1000),
              end=Timestamp(micros=x['end'] * 1000)),
      'beam:coder:iterable:v1': lambda x, parser: list(map(parser, x)),
      'beam:coder:global_window:v1': lambda x: window.GlobalWindow(),
      'beam:coder:windowed_value:v1':
          lambda x, value_parser, window_parser: windowed_value.create(
              value_parser(x['value']), x['timestamp'] * 1000,
              tuple([window_parser(w) for w in x['windows']])),
      'beam:coder:timer:v1':
          lambda x, payload_parser: dict(
              payload=payload_parser(x['payload']),
              timestamp=Timestamp(micros=x['timestamp'] * 1000)),
      'beam:coder:double:v1': parse_float,
  }

  def test_standard_coders(self):
    for name, spec in _load_test_cases(STANDARD_CODERS_YAML):
      logging.info('Executing %s test.', name)
      self._run_standard_coder(name, spec)

  def _run_standard_coder(self, name, spec):
    def assert_equal(actual, expected):
      """Handle nan values which self.assertEqual fails on."""
      if (isinstance(actual, float)
          and isinstance(expected, float)
          and math.isnan(actual)
          and math.isnan(expected)):
        return
      self.assertEqual(actual, expected)

    coder = self.parse_coder(spec['coder'])
    parse_value = self.json_value_parser(spec['coder'])
    nested_list = [spec['nested']] if 'nested' in spec else [True, False]
    for nested in nested_list:
      for expected_encoded, json_value in spec['examples'].items():
        value = parse_value(json_value)
        expected_encoded = expected_encoded.encode('latin1')
        if not spec['coder'].get('non_deterministic', False):
          actual_encoded = encode_nested(coder, value, nested)
          if self.fix and actual_encoded != expected_encoded:
            self.to_fix[spec['index'], expected_encoded] = actual_encoded
          else:
            self.assertEqual(expected_encoded, actual_encoded)
            decoded = decode_nested(coder, expected_encoded, nested)
            assert_equal(decoded, value)
        else:
          # Only verify decoding for a non-deterministic coder
          self.assertEqual(decode_nested(coder, expected_encoded, nested),
                           value)

  def parse_coder(self, spec):
    context = pipeline_context.PipelineContext()
    coder_id = str(hash(str(spec)))
    component_ids = [context.coders.get_id(self.parse_coder(c))
                     for c in spec.get('components', ())]
    context.coders.put_proto(coder_id, beam_runner_api_pb2.Coder(
        spec=beam_runner_api_pb2.FunctionSpec(
            urn=spec['urn'], payload=spec.get('payload')),
        component_coder_ids=component_ids))
    return context.coders.get_by_id(coder_id)

  def json_value_parser(self, coder_spec):
    component_parsers = [
        self.json_value_parser(c) for c in coder_spec.get('components', ())]
    return lambda x: self._urn_to_json_value_parser[coder_spec['urn']](
        x, *component_parsers)

  # Used when --fix is passed.

  fix = False
  to_fix = {}

  @classmethod
  def tearDownClass(cls):
    if cls.fix and cls.to_fix:
      print("FIXING", len(cls.to_fix), "TESTS")
      doc_sep = '\n---\n'
      docs = open(STANDARD_CODERS_YAML).read().split(doc_sep)

      def quote(s):
        return json.dumps(s.decode('latin1')).replace(r'\u0000', r'\0')
      for (doc_ix, expected_encoded), actual_encoded in cls.to_fix.items():
        print(quote(expected_encoded), "->", quote(actual_encoded))
        docs[doc_ix] = docs[doc_ix].replace(
            quote(expected_encoded) + ':', quote(actual_encoded) + ':')
      open(STANDARD_CODERS_YAML, 'w').write(doc_sep.join(docs))


def encode_nested(coder, value, nested=True):
  out = coder_impl.create_OutputStream()
  coder.get_impl().encode_to_stream(value, out, nested)
  return out.get()


def decode_nested(coder, encoded, nested=True):
  return coder.get_impl().decode_from_stream(
      coder_impl.create_InputStream(encoded), nested)


if __name__ == '__main__':
  if '--fix' in sys.argv:
    StandardCodersTest.fix = True
    sys.argv.remove('--fix')
  unittest.main()