import numpy as np

from pandas import Categorical, Series
import pandas._testing as tm


class TestCategoricalComparisons:
    def test_categorical_nan_equality(self):
        cat = Series(Categorical(["a", "b", "c", np.nan]))
        expected = Series([True, True, True, False])
        result = cat == cat
        tm.assert_series_equal(result, expected)