code: def test_astype_category(self):
      obj = period_range("2000", periods=2, name="idx")
      result = obj.astype("category")
      expected = CategoricalIndex(
          [
              Period("2000-01-01", freq="D"),
              Period("2000-01-02", freq="D"),
          ],
          name="idx",
      )
      tm.assert_index_equal(result, expected)
  
      result = obj._data.astype("category")
      expected = expected.values
      tm.assert_categorical_equal(result, expected)
  
file_path: pandas/pandas/tests/indexes/period/methods/test_astype.py
imports: import numpy
  import pytest
  from pandas import CategoricalIndex, DatetimeIndex, Index, NaT, Period, PeriodIndex, period_range
  import pandas._testing
label_desc: Use image node_id 6 for calling the TestPeriodIndexAsType obj's underlying member method code with example usage: obj.test_astype_category() without return types