code: def test_categorical_unexpected_categories(all_parsers):
      parser = all_parsers
      dtype = {"b": CategoricalDtype(["a", "b", "d", "e"])}
  
      data = "b\nd\na\nc\nd"  # Unexpected c
      expected = DataFrame(
          {"b": Categorical(list("dacd"), dtype=dtype["b"])}
      )
  
      result = parser.read_csv(StringIO(data), dtype=dtype)
      tm.assert_frame_equal(result, expected)
  
imports: from io import StringIO
  import os
  import numpy
  import pytest
  from pandas._libs import parsers
  from pandas.core.dtypes.dtypes import CategoricalDtype
  import pandas
  from pandas import Categorical, DataFrame, Timestamp
  import pandas._testing
label_desc: Use image node_id 17 for calling a global function with example usage: test_categorical_unexpected_categories(all_parsers) without return types