apache/beam · error · TypeError

f' of test specification must be an object, got

Error message

f'{attr_type} {ix} of test specification {identifier} must be an object, got {type(attr_item)}'

What it means

One entry inside a mock_inputs/mock_outputs/expected_outputs/expected_inputs list is not a mapping. Each entry must be an object with at least a 'name' key and an 'elements' key; this guard fires when an entry (e.g. a bare string or number) cannot be treated as a per-input/output spec.

Solutions

1. Make each list entry a mapping with 'name' and 'elements' keys, e.g. {name: input1, elements: [...]}
2. Quote names that could be parsed as scalars and ensure YAML indentation places entries under the attribute list

When it happens

Trigger: Thrown at sdks/python/apache_beam/yaml/yaml_testing.py:184 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/6bc950e0ba12d2f4. Report an issue: GitHub.

Appendix: source

Thrown at sdks/python/apache_beam/yaml/yaml_testing.py:184

          'allowed_sources',
      ])
  if unknown_attrs:
    raise ValueError(
        f'test specification {identifier} '
        f'has unknown attributes {list(unknown_attrs)}')

  for attr_type in ('mock_inputs',
                    'mock_outputs',
                    'expected_outputs',
                    'expected_inputs'):
    attr = test_spec.get(attr_type, [])
    if not isinstance(attr, list):
      raise TypeError(
          f'{attr_type} of test specification {identifier} '
          f'must be a list, got {type(attr_type)}')
    for ix, attr_item in enumerate(attr):
      if not isinstance(attr_item, dict):
        raise TypeError(
            f'{attr_type} {ix} of test specification {identifier} '
            f'must be an object, got {type(attr_item)}')
      if 'name' not in attr_item:
        raise TypeError(
            f'{attr_type} {ix} of test specification {identifier} '
            f'missing a name')
      if 'elements' not in attr_item:
        raise TypeError(
            f'{attr_type} {ix} of test specification {identifier} '
            f'missing a elements')
      if not isinstance(attr_item['elements'], list):
        raise TypeError(
            f'{attr_type} {ix} of test specification {identifier} '
            f'must be a list, got {type(attr_item["elements"])}')


def inject_test_tranforms(spec, test_spec, fix_failures):
  validate_test_spec(test_spec)

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