Source code for apache_beam.testing.util

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"""Utilities for testing Beam pipelines."""

# pytype: skip-file

import collections
import glob
import io
import tempfile
from typing import Iterable

from apache_beam import pvalue
from apache_beam.transforms import window
from apache_beam.transforms.core import Create
from apache_beam.transforms.core import DoFn
from apache_beam.transforms.core import Map
from apache_beam.transforms.core import ParDo
from apache_beam.transforms.core import WindowInto
from apache_beam.transforms.ptransform import PTransform
from apache_beam.transforms.ptransform import ptransform_fn
from apache_beam.transforms.util import CoGroupByKey

__all__ = [
    # open_shards is internal and has no backwards compatibility guarantees.

class BeamAssertException(Exception):
  """Exception raised by matcher classes used by assert_that transform."""


# Used for reifying timestamps and windows for assert_that matchers.
TestWindowedValue = collections.namedtuple(
    'TestWindowedValue', 'value timestamp windows')

def contains_in_any_order(iterable):
  """Creates an object that matches another iterable if they both have the
  same count of items.

    iterable: An iterable of hashable objects.
  class InAnyOrder(object):
    def __init__(self, iterable):
      self._counter = collections.Counter(iterable)

    def __eq__(self, other):
      return self._counter == collections.Counter(other)

    def __hash__(self):
      return hash(self._counter)

    def __repr__(self):
      return "InAnyOrder(%s)" % self._counter

  return InAnyOrder(iterable)

class _EqualToPerWindowMatcher(object):
  def __init__(self, expected_window_to_elements):
    self._expected_window_to_elements = expected_window_to_elements

  def __call__(self, value):
    # Short-hand.
    _expected = self._expected_window_to_elements

    # Match the given windowed value to an expected window. Fails if the window
    # doesn't exist or the element wasn't found in the window.
    def match(windowed_value):
      actual = windowed_value.value
      window_key =[0]
      except KeyError:
        raise BeamAssertException(
            'Failed assert: window {} not found in any expected ' \
            'windows {}'.format(window_key, list(_expected.keys())))\

      # Remove any matched elements from the window. This is used later on to
      # assert that all elements in the window were matched with actual
      # elements.
      except ValueError:
        raise BeamAssertException(
            'Failed assert: element {} not found in window ' \
            '{}:{}'.format(actual, window_key, _expected[window_key]))\

    # Run the matcher for each window and value pair. Fails if the
    # windowed_value is not a TestWindowedValue.
    for windowed_value in value:
      if not isinstance(windowed_value, TestWindowedValue):
        raise BeamAssertException(
            'Failed assert: Received element {} is not of type ' \
            'TestWindowedValue. Did you forget to set reify_windows=True ' \
            'on the assertion?'.format(windowed_value))

    # Finally, some elements may not have been matched. Assert that we removed
    # all the elements that we received from the expected list. If the list is
    # non-empty, then there are unmatched elements.
    for win in _expected:
      if _expected[win]:
        raise BeamAssertException(
            'Failed assert: unmatched elements {} in window {}'.format(
                _expected[win], win))

[docs]def equal_to_per_window(expected_window_to_elements): """Matcher used by assert_that to check to assert expected windows. The 'assert_that' statement must have reify_windows=True. This assertion works when elements are emitted and are finally checked at the end of the window. Arguments: expected_window_to_elements: A dictionary where the keys are the windows to check and the values are the elements associated with each window. """ return _EqualToPerWindowMatcher(expected_window_to_elements)
# Note that equal_to checks if expected and actual are permutations of each # other. However, only permutations of the top level are checked. Therefore # [1,2] and [2,1] are considered equal and [[1,2]] and [[2,1]] are not.
[docs]def equal_to(expected, equals_fn=None): def _equal(actual, equals_fn=equals_fn): expected_list = list(expected) # Try to compare actual and expected by sorting. This fails with a # TypeError in Python 3 if different types are present in the same # collection. It can also raise false negatives for types that don't have # a deterministic sort order, like pyarrow Tables as of 0.14.1 if not equals_fn: equals_fn = lambda e, a: e == a try: sorted_expected = sorted(expected) sorted_actual = sorted(actual) if sorted_expected == sorted_actual: return except TypeError: pass # Slower method, used in two cases: # 1) If sorted expected != actual, use this method to verify the inequality. # This ensures we don't raise any false negatives for types that don't # have a deterministic sort order. # 2) As a fallback if we encounter a TypeError in python 3. this method # works on collections that have different types. unexpected = [] for element in actual: found = False for i, v in enumerate(expected_list): if equals_fn(v, element): found = True expected_list.pop(i) break if not found: unexpected.append(element) if unexpected or expected_list: msg = 'Failed assert: %r == %r' % (expected, actual) if unexpected: msg = msg + ', unexpected elements %r' % unexpected if expected_list: msg = msg + ', missing elements %r' % expected_list raise BeamAssertException(msg) return _equal
[docs]def matches_all(expected): """Matcher used by assert_that to check a set of matchers. Args: expected: A list of elements or hamcrest matchers to be used to match the elements of a single PCollection. """ def _matches(actual): from hamcrest.core import assert_that as hamcrest_assert from hamcrest.library.collection import contains_inanyorder expected_list = list(expected) hamcrest_assert(actual, contains_inanyorder(*expected_list)) return _matches
[docs]def is_empty(): def _empty(actual): actual = list(actual) if actual: raise BeamAssertException('Failed assert: [] == %r' % actual) return _empty
[docs]def is_not_empty(): """ This is test method which makes sure that the pcol is not empty and it has some data in it. :return: """ def _not_empty(actual): actual = list(actual) if not actual: raise BeamAssertException('Failed assert: pcol is empty') return _not_empty
[docs]def assert_that( actual, matcher, label='assert_that', reify_windows=False, use_global_window=True): """A PTransform that checks a PCollection has an expected value. Note that assert_that should be used only for testing pipelines since the check relies on materializing the entire PCollection being checked. Args: actual: A PCollection. matcher: A matcher function taking as argument the actual value of a materialized PCollection. The matcher validates this actual value against expectations and raises BeamAssertException if they are not met. label: Optional string label. This is needed in case several assert_that transforms are introduced in the same pipeline. reify_windows: If True, matcher is passed a list of TestWindowedValue. use_global_window: If False, matcher is passed a dictionary of (k, v) = (window, elements in the window). Returns: Ignored. """ assert isinstance(actual, pvalue.PCollection), ( '%s is not a supported type for Beam assert' % type(actual)) if isinstance(matcher, _EqualToPerWindowMatcher): reify_windows = True use_global_window = True class ReifyTimestampWindow(DoFn): def process( self, element, timestamp=DoFn.TimestampParam, window=DoFn.WindowParam): # This returns TestWindowedValue instead of # beam.utils.windowed_value.WindowedValue because ParDo will extract # the timestamp and window out of the latter. return [TestWindowedValue(element, timestamp, [window])] class AddWindow(DoFn): def process(self, element, window=DoFn.WindowParam): yield element, window class AssertThat(PTransform): def expand(self, pcoll): if reify_windows: pcoll = pcoll | ParDo(ReifyTimestampWindow()) keyed_singleton = pcoll.pipeline | Create([(None, None)]) keyed_singleton.is_bounded = True if use_global_window: pcoll = pcoll | WindowInto(window.GlobalWindows()) keyed_actual = pcoll | 'ToVoidKey' >> Map(lambda v: (None, v)) keyed_actual.is_bounded = True # This is a CoGroupByKey so that the matcher always runs, even if the # PCollection is empty. plain_actual = ((keyed_singleton, keyed_actual) | 'Group' >> CoGroupByKey() | 'Unkey' >> Map(lambda k_values: k_values[1][1])) if not use_global_window: plain_actual = plain_actual | 'AddWindow' >> ParDo(AddWindow()) plain_actual = plain_actual | 'Match' >> Map(matcher) def default_label(self): return label actual | AssertThat() # pylint: disable=expression-not-assigned
@ptransform_fn def AssertThat(pcoll, *args, **kwargs): """Like assert_that, but as an applicable PTransform.""" return assert_that(pcoll, *args, **kwargs)
[docs]def open_shards(glob_pattern, mode='rt', encoding='utf-8'): """Returns a composite file of all shards matching the given glob pattern. Args: glob_pattern (str): Pattern used to match files which should be opened. mode (str): Specify the mode in which the file should be opened. For available modes, check documentation. encoding (str): Name of the encoding used to decode or encode the file. This should only be used in text mode. Returns: A stream with the contents of the opened files. """ if 'b' in mode: encoding = None with tempfile.NamedTemporaryFile(delete=False) as out_file: for shard in glob.glob(glob_pattern): with open(shard, 'rb') as in_file: out_file.write( concatenated_file_name = return, mode, encoding=encoding)
def _sort_lists(result): if isinstance(result, list): return sorted(result) elif isinstance(result, tuple): return tuple(_sort_lists(e) for e in result) elif isinstance(result, dict): return {k: _sort_lists(v) for k, v in result.items()} elif isinstance(result, Iterable) and not isinstance(result, str): return sorted(result) else: return result # A utility transform that recursively sorts lists for easier testing. SortLists = Map(_sort_lists)