text: from typing import Type, Union
  
  import numpy as np
  import pytest
  
  from pandas._libs import OutOfBoundsDatetime
  
  import pandas as pd
  from pandas.core.arrays import DatetimeArray, PeriodArray, TimedeltaArray
  from pandas.core.indexes.datetimes import DatetimeIndex
  from pandas.core.indexes.period import PeriodIndex
  from pandas.core.indexes.timedeltas import TimedeltaIndex
  import pandas.util.testing as tm
  
  
  # TODO: more freq variants
  @pytest.fixture(params=["D", "B", "W", "M", "Q", "Y"])
  def period_index(request):
      """
      A fixture to provide PeriodIndex objects with different frequencies.
  
      Most PeriodArray behavior is already tested in PeriodIndex tests,
      so here we just test that the PeriodArray behavior matches
      the PeriodIndex behavior.
      """
      freqstr = request.param
      # TODO: non-monotone indexes; NaTs, different start dates
      pi = pd.period_range(start=pd.Timestamp("2000-01-01"), periods=100, freq=freqstr)
      return pi
  
  
  @pytest.fixture(params=["D", "B", "W", "M", "Q", "Y"])
  def datetime_index(request):
      """
      A fixture to provide DatetimeIndex objects with different frequencies.
  
      Most DatetimeArray behavior is already tested in DatetimeIndex tests,
      so here we just test that the DatetimeArray behavior matches
      the DatetimeIndex behavior.
      """
      freqstr = request.param
      # TODO: non-monotone indexes; NaTs, different start dates, timezones
      pi = pd.date_range(start=pd.Timestamp("2000-01-01"), periods=100, freq=freqstr)
      return pi
  
  
  @pytest.fixture
  def timedelta_index(request):
      """
      A fixture to provide TimedeltaIndex objects with different frequencies.
       Most TimedeltaArray behavior is already tested in TimedeltaIndex tests,
      so here we just test that the TimedeltaArray behavior matches
      the TimedeltaIndex behavior.
      """
      # TODO: flesh this out
      return pd.TimedeltaIndex(["1 Day", "3 Hours", "NaT"])
  
  
  class SharedTests:
      index_cls = None  # type: Type[Union[DatetimeIndex, PeriodIndex, TimedeltaIndex]]
  
      def test_compare_len1_raises(self):
          # make sure we raise when comparing with different lengths, specific
          #  to the case where one has length-1, which numpy would broadcast
          data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
  
          idx = self.index_cls._simple_new(data, freq="D")
          arr = self.array_cls(idx)
  
          with pytest.raises(ValueError, match="Lengths must match"):
              arr == arr[:1]
  
          # test the index classes while we're at it, GH#23078
          with pytest.raises(ValueError, match="Lengths must match"):
              idx <= idx[[0]]
  
      def test_take(self):
          data = np.arange(100, dtype="i8") * 24 * 3600 * 10 ** 9
          np.random.shuffle(data)
  
          idx = self.index_cls._simple_new(data, freq="D")
          arr = self.array_cls(idx)
  
          takers = [1, 4, 94]
          result = arr.take(takers)
          expected = idx.take(takers)
  
          tm.assert_index_equal(self.index_cls(result), expected)
  
          takers = np.array([1, 4, 94])
          result = arr.take(takers)
          expected = idx.take(takers)
  
          tm.assert_index_equal(self.index_cls(result), expected)
  
      def test_take_fill(self):
          data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
  
          idx = self.index_cls._simple_new(data, freq="D")
          arr = self.array_cls(idx)
  
          result = arr.take([-1, 1], allow_fill=True, fill_value=None)
          assert result[0] is pd.NaT
  
          result = arr.take([-1, 1], allow_fill=True, fill_value=np.nan)
          assert result[0] is pd.NaT
  
          result = arr.take([-1, 1], allow_fill=True, fill_value=pd.NaT)
          assert result[0] is pd.NaT
  
          with pytest.raises(ValueError):
              arr.take([0, 1], allow_fill=True, fill_value=2)
  
          with pytest.raises(ValueError):
              arr.take([0, 1], allow_fill=True, fill_value=2.0)
  
          with pytest.raises(ValueError):
              arr.take([0, 1], allow_fill=True, fill_value=pd.Timestamp.now().time)
  
      def test_concat_same_type(self):
          data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
  
          idx = self.index_cls._simple_new(data, freq="D").insert(0, pd.NaT)
          arr = self.array_cls(idx)
  
          result = arr._concat_same_type([arr[:-1], arr[1:], arr])
          expected = idx._concat_same_dtype([idx[:-1], idx[1:], idx], None)
  
          tm.assert_index_equal(self.index_cls(result), expected)
  
      def test_unbox_scalar(self):
          data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
          arr = self.array_cls(data, freq="D")
          result = arr._unbox_scalar(arr[0])
          assert isinstance(result, int)
  
          result = arr._unbox_scalar(pd.NaT)
          assert isinstance(result, int)
  
          with pytest.raises(ValueError):
              arr._unbox_scalar("foo")
  
      def test_check_compatible_with(self):
          data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
          arr = self.array_cls(data, freq="D")
  
          arr._check_compatible_with(arr[0])
          arr._check_compatible_with(arr[:1])
          arr._check_compatible_with(pd.NaT)
  
      def test_scalar_from_string(self):
          data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
          arr = self.array_cls(data, freq="D")
          result = arr._scalar_from_string(str(arr[0]))
          assert result == arr[0]
  
      def test_reduce_invalid(self):
          data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
          arr = self.array_cls(data, freq="D")
  
          with pytest.raises(TypeError, match="cannot perform"):
              arr._reduce("not a method")
  
      @pytest.mark.parametrize("method", ["pad", "backfill"])
      def test_fillna_method_doesnt_change_orig(self, method):
          data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
          arr = self.array_cls(data, freq="D")
          arr[4] = pd.NaT
  
          fill_value = arr[3] if method == "pad" else arr[5]
  
          result = arr.fillna(method=method)
          assert result[4] == fill_value
  
          # check that the original was not changed
          assert arr[4] is pd.NaT
  
      def test_searchsorted(self):
          data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
          arr = self.array_cls(data, freq="D")
  
          # scalar
          result = arr.searchsorted(arr[1])
          assert result == 1
  
          result = arr.searchsorted(arr[2], side="right")
          assert result == 3
  
          # own-type
          result = arr.searchsorted(arr[1:3])
          expected = np.array([1, 2], dtype=np.intp)
          tm.assert_numpy_array_equal(result, expected)
  
          result = arr.searchsorted(arr[1:3], side="right")
          expected = np.array([2, 3], dtype=np.intp)
          tm.assert_numpy_array_equal(result, expected)
  
          # Following numpy convention, NaT goes at the beginning
          #  (unlike NaN which goes at the end)
          result = arr.searchsorted(pd.NaT)
          assert result == 0
  
      def test_setitem(self):
          data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
          arr = self.array_cls(data, freq="D")
  
          arr[0] = arr[1]
          expected = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
          expected[0] = expected[1]
  
          tm.assert_numpy_array_equal(arr.asi8, expected)
  
          arr[:2] = arr[-2:]
          expected[:2] = expected[-2:]
          tm.assert_numpy_array_equal(arr.asi8, expected)
  
      def test_setitem_raises(self):
          data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
          arr = self.array_cls(data, freq="D")
          val = arr[0]
  
          with pytest.raises(IndexError, match="index 12 is out of bounds"):
              arr[12] = val
  
          with pytest.raises(TypeError, match="'value' should be a.* 'object'"):
              arr[0] = object()
  
  
  class TestDatetimeArray(SharedTests):
      index_cls = pd.DatetimeIndex
      array_cls = DatetimeArray
  
      def test_round(self, tz_naive_fixture):
          # GH#24064
          tz = tz_naive_fixture
          dti = pd.date_range("2016-01-01 01:01:00", periods=3, freq="H", tz=tz)
  
          result = dti.round(freq="2T")
          expected = dti - pd.Timedelta(minutes=1)
          tm.assert_index_equal(result, expected)
  
      def test_array_interface(self, datetime_index):
          arr = DatetimeArray(datetime_index)
  
          # default asarray gives the same underlying data (for tz naive)
          result = np.asarray(arr)
          expected = arr._data
          assert result is expected
          tm.assert_numpy_array_equal(result, expected)
          result = np.array(arr, copy=False)
          assert result is expected
          tm.assert_numpy_array_equal(result, expected)
  
          # specifying M8[ns] gives the same result as default
          result = np.asarray(arr, dtype="datetime64[ns]")
          expected = arr._data
          assert result is expected
          tm.assert_numpy_array_equal(result, expected)
          result = np.array(arr, dtype="datetime64[ns]", copy=False)
          assert result is expected
          tm.assert_numpy_array_equal(result, expected)
          result = np.array(arr, dtype="datetime64[ns]")
          assert result is not expected
          tm.assert_numpy_array_equal(result, expected)
  
          # to object dtype
          result = np.asarray(arr, dtype=object)
          expected = np.array(list(arr), dtype=object)
          tm.assert_numpy_array_equal(result, expected)
  
          # to other dtype always copies
          result = np.asarray(arr, dtype="int64")
          assert result is not arr.asi8
          assert not np.may_share_memory(arr, result)
          expected = arr.asi8.copy()
          tm.assert_numpy_array_equal(result, expected)
  
          # other dtypes handled by numpy
          for dtype in ["float64", str]:
              result = np.asarray(arr, dtype=dtype)
              expected = np.asarray(arr).astype(dtype)
              tm.assert_numpy_array_equal(result, expected)
  
      def test_array_object_dtype(self, tz_naive_fixture):
          # GH#23524
          tz = tz_naive_fixture
          dti = pd.date_range("2016-01-01", periods=3, tz=tz)
          arr = DatetimeArray(dti)
  
          expected = np.array(list(dti))
  
          result = np.array(arr, dtype=object)
          tm.assert_numpy_array_equal(result, expected)
  
          # also test the DatetimeIndex method while we're at it
          result = np.array(dti, dtype=object)
          tm.assert_numpy_array_equal(result, expected)
  
      def test_array_tz(self, tz_naive_fixture):
          # GH#23524
          tz = tz_naive_fixture
          dti = pd.date_range("2016-01-01", periods=3, tz=tz)
          arr = DatetimeArray(dti)
  
          expected = dti.asi8.view("M8[ns]")
          result = np.array(arr, dtype="M8[ns]")
          tm.assert_numpy_array_equal(result, expected)
  
          result = np.array(arr, dtype="datetime64[ns]")
          tm.assert_numpy_array_equal(result, expected)
  
          # check that we are not making copies when setting copy=False
          result = np.array(arr, dtype="M8[ns]", copy=False)
          assert result.base is expected.base
          assert result.base is not None
          result = np.array(arr, dtype="datetime64[ns]", copy=False)
          assert result.base is expected.base
          assert result.base is not None
  
      def test_array_i8_dtype(self, tz_naive_fixture):
          tz = tz_naive_fixture
          dti = pd.date_range("2016-01-01", periods=3, tz=tz)
          arr = DatetimeArray(dti)
  
          expected = dti.asi8
          result = np.array(arr, dtype="i8")
          tm.assert_numpy_array_equal(result, expected)
  
          result = np.array(arr, dtype=np.int64)
          tm.assert_numpy_array_equal(result, expected)
  
          # check that we are still making copies when setting copy=False
          result = np.array(arr, dtype="i8", copy=False)
          assert result.base is not expected.base
          assert result.base is None
  
      def test_from_array_keeps_base(self):
          # Ensure that DatetimeArray._data.base isn't lost.
          arr = np.array(["2000-01-01", "2000-01-02"], dtype="M8[ns]")
          dta = DatetimeArray(arr)
  
          assert dta._data is arr
          dta = DatetimeArray(arr[:0])
          assert dta._data.base is arr
  
      def test_from_dti(self, tz_naive_fixture):
          tz = tz_naive_fixture
          dti = pd.date_range("2016-01-01", periods=3, tz=tz)
          arr = DatetimeArray(dti)
          assert list(dti) == list(arr)
  
          # Check that Index.__new__ knows what to do with DatetimeArray
          dti2 = pd.Index(arr)
          assert isinstance(dti2, pd.DatetimeIndex)
          assert list(dti2) == list(arr)
  
      def test_astype_object(self, tz_naive_fixture):
          tz = tz_naive_fixture
          dti = pd.date_range("2016-01-01", periods=3, tz=tz)
          arr = DatetimeArray(dti)
          asobj = arr.astype("O")
          assert isinstance(asobj, np.ndarray)
          assert asobj.dtype == "O"
          assert list(asobj) == list(dti)
  
      @pytest.mark.parametrize("freqstr", ["D", "B", "W", "M", "Q", "Y"])
      def test_to_perioddelta(self, datetime_index, freqstr):
          # GH#23113
          dti = datetime_index
          arr = DatetimeArray(dti)
  
          expected = dti.to_perioddelta(freq=freqstr)
          result = arr.to_perioddelta(freq=freqstr)
          assert isinstance(result, TimedeltaArray)
  
          # placeholder until these become actual EA subclasses and we can use
          #  an EA-specific tm.assert_ function
          tm.assert_index_equal(pd.Index(result), pd.Index(expected))
  
      @pytest.mark.parametrize("freqstr", ["D", "B", "W", "M", "Q", "Y"])
      def test_to_period(self, datetime_index, freqstr):
          dti = datetime_index
          arr = DatetimeArray(dti)
  
          expected = dti.to_period(freq=freqstr)
          result = arr.to_period(freq=freqstr)
          assert isinstance(result, PeriodArray)
  
          # placeholder until these become actual EA subclasses and we can use
          #  an EA-specific tm.assert_ function
          tm.assert_index_equal(pd.Index(result), pd.Index(expected))
  
      @pytest.mark.parametrize("propname", pd.DatetimeIndex._bool_ops)
      def test_bool_properties(self, datetime_index, propname):
          # in this case _bool_ops is just `is_leap_year`
          dti = datetime_index
          arr = DatetimeArray(dti)
          assert dti.freq == arr.freq
  
          result = getattr(arr, propname)
          expected = np.array(getattr(dti, propname), dtype=result.dtype)
  
          tm.assert_numpy_array_equal(result, expected)
  
      @pytest.mark.parametrize("propname", pd.DatetimeIndex._field_ops)
      def test_int_properties(self, datetime_index, propname):
          dti = datetime_index
          arr = DatetimeArray(dti)
  
          result = getattr(arr, propname)
          expected = np.array(getattr(dti, propname), dtype=result.dtype)
  
          tm.assert_numpy_array_equal(result, expected)
  
      def test_take_fill_valid(self, datetime_index, tz_naive_fixture):
          dti = datetime_index.tz_localize(tz_naive_fixture)
          arr = DatetimeArray(dti)
  
          now = pd.Timestamp.now().tz_localize(dti.tz)
          result = arr.take([-1, 1], allow_fill=True, fill_value=now)
          assert result[0] == now
  
          with pytest.raises(ValueError):
              # fill_value Timedelta invalid
              arr.take([-1, 1], allow_fill=True, fill_value=now - now)
  
          with pytest.raises(ValueError):
              # fill_value Period invalid
              arr.take([-1, 1], allow_fill=True, fill_value=pd.Period("2014Q1"))
  
          tz = None if dti.tz is not None else "US/Eastern"
          now = pd.Timestamp.now().tz_localize(tz)
          with pytest.raises(TypeError):
              # Timestamp with mismatched tz-awareness
              arr.take([-1, 1], allow_fill=True, fill_value=now)
  
          with pytest.raises(ValueError):
              # require NaT, not iNaT, as it could be confused with an integer
              arr.take([-1, 1], allow_fill=True, fill_value=pd.NaT.value)
  
      def test_concat_same_type_invalid(self, datetime_index):
          # different timezones
          dti = datetime_index
          arr = DatetimeArray(dti)
  
          if arr.tz is None:
              other = arr.tz_localize("UTC")
          else:
              other = arr.tz_localize(None)
  
          with pytest.raises(AssertionError):
              arr._concat_same_type([arr, other])
  
      def test_concat_same_type_different_freq(self):
          # we *can* concatenate DTI with different freqs.
          a = DatetimeArray(pd.date_range("2000", periods=2, freq="D", tz="US/Central"))
          b = DatetimeArray(pd.date_range("2000", periods=2, freq="H", tz="US/Central"))
          result = DatetimeArray._concat_same_type([a, b])
          expected = DatetimeArray(
              pd.to_datetime(
                  [
                      "2000-01-01 00:00:00",
                      "2000-01-02 00:00:00",
                      "2000-01-01 00:00:00",
                      "2000-01-01 01:00:00",
                  ]
              ).tz_localize("US/Central")
          )
  
          tm.assert_datetime_array_equal(result, expected)
  
      def test_strftime(self, datetime_index):
          arr = DatetimeArray(datetime_index)
  
          result = arr.strftime("%Y %b")
          expected = np.array([ts.strftime("%Y %b") for ts in arr], dtype=object)
          tm.assert_numpy_array_equal(result, expected)
  
      def test_strftime_nat(self):
          # GH 29578
          arr = DatetimeArray(DatetimeIndex(["2019-01-01", pd.NaT]))
  
          result = arr.strftime("%Y-%m-%d")
          expected = np.array(["2019-01-01", np.nan], dtype=object)
          tm.assert_numpy_array_equal(result, expected)
  
  
  class TestTimedeltaArray(SharedTests):
      index_cls = pd.TimedeltaIndex
      array_cls = TimedeltaArray
  
      def test_from_tdi(self):
          tdi = pd.TimedeltaIndex(["1 Day", "3 Hours"])
          arr = TimedeltaArray(tdi)
          assert list(arr) == list(tdi)
  
          # Check that Index.__new__ knows what to do with TimedeltaArray
          tdi2 = pd.Index(arr)
          assert isinstance(tdi2, pd.TimedeltaIndex)
          assert list(tdi2) == list(arr)
  
      def test_astype_object(self):
          tdi = pd.TimedeltaIndex(["1 Day", "3 Hours"])
          arr = TimedeltaArray(tdi)
          asobj = arr.astype("O")
          assert isinstance(asobj, np.ndarray)
          assert asobj.dtype == "O"
          assert list(asobj) == list(tdi)
  
      def test_to_pytimedelta(self, timedelta_index):
          tdi = timedelta_index
          arr = TimedeltaArray(tdi)
  
          expected = tdi.to_pytimedelta()
          result = arr.to_pytimedelta()
  
          tm.assert_numpy_array_equal(result, expected)
  
      def test_total_seconds(self, timedelta_index):
          tdi = timedelta_index
          arr = TimedeltaArray(tdi)
  
          expected = tdi.total_seconds()
          result = arr.total_seconds()
  
          tm.assert_numpy_array_equal(result, expected.values)
  
      @pytest.mark.parametrize("propname", pd.TimedeltaIndex._field_ops)
      def test_int_properties(self, timedelta_index, propname):
          tdi = timedelta_index
          arr = TimedeltaArray(tdi)
  
          result = getattr(arr, propname)
          expected = np.array(getattr(tdi, propname), dtype=result.dtype)
  
          tm.assert_numpy_array_equal(result, expected)
  
      def test_array_interface(self, timedelta_index):
          arr = TimedeltaArray(timedelta_index)
  
          # default asarray gives the same underlying data
          result = np.asarray(arr)
          expected = arr._data
          assert result is expected
          tm.assert_numpy_array_equal(result, expected)
          result = np.array(arr, copy=False)
          assert result is expected
          tm.assert_numpy_array_equal(result, expected)
  
          # specifying m8[ns] gives the same result as default
          result = np.asarray(arr, dtype="timedelta64[ns]")
          expected = arr._data
          assert result is expected
          tm.assert_numpy_array_equal(result, expected)
          result = np.array(arr, dtype="timedelta64[ns]", copy=False)
          assert result is expected
          tm.assert_numpy_array_equal(result, expected)
          result = np.array(arr, dtype="timedelta64[ns]")
          assert result is not expected
          tm.assert_numpy_array_equal(result, expected)
  
          # to object dtype
          result = np.asarray(arr, dtype=object)
          expected = np.array(list(arr), dtype=object)
          tm.assert_numpy_array_equal(result, expected)
  
          # to other dtype always copies
          result = np.asarray(arr, dtype="int64")
          assert result is not arr.asi8
          assert not np.may_share_memory(arr, result)
          expected = arr.asi8.copy()
          tm.assert_numpy_array_equal(result, expected)
  
          # other dtypes handled by numpy
          for dtype in ["float64", str]:
              result = np.asarray(arr, dtype=dtype)
              expected = np.asarray(arr).astype(dtype)
              tm.assert_numpy_array_equal(result, expected)
  
      def test_take_fill_valid(self, timedelta_index):
          tdi = timedelta_index
          arr = TimedeltaArray(tdi)
  
          td1 = pd.Timedelta(days=1)
          result = arr.take([-1, 1], allow_fill=True, fill_value=td1)
          assert result[0] == td1
  
          now = pd.Timestamp.now()
          with pytest.raises(ValueError):
              # fill_value Timestamp invalid
              arr.take([0, 1], allow_fill=True, fill_value=now)
  
          with pytest.raises(ValueError):
              # fill_value Period invalid
              arr.take([0, 1], allow_fill=True, fill_value=now.to_period("D"))
  
  
  class TestPeriodArray(SharedTests):
      index_cls = pd.PeriodIndex
      array_cls = PeriodArray
  
      def test_from_pi(self, period_index):
          pi = period_index
          arr = PeriodArray(pi)
          assert list(arr) == list(pi)
  
          # Check that Index.__new__ knows what to do with PeriodArray
          pi2 = pd.Index(arr)
          assert isinstance(pi2, pd.PeriodIndex)
          assert list(pi2) == list(arr)
  
      def test_astype_object(self, period_index):
          pi = period_index
          arr = PeriodArray(pi)
          asobj = arr.astype("O")
          assert isinstance(asobj, np.ndarray)
          assert asobj.dtype == "O"
          assert list(asobj) == list(pi)
  
      @pytest.mark.parametrize("how", ["S", "E"])
      def test_to_timestamp(self, how, period_index):
          pi = period_index
          arr = PeriodArray(pi)
  
          expected = DatetimeArray(pi.to_timestamp(how=how))
          result = arr.to_timestamp(how=how)
          assert isinstance(result, DatetimeArray)
  
          # placeholder until these become actual EA subclasses and we can use
          #  an EA-specific tm.assert_ function
          tm.assert_index_equal(pd.Index(result), pd.Index(expected))
  
      def test_to_timestamp_out_of_bounds(self):
          # GH#19643 previously overflowed silently
          pi = pd.period_range("1500", freq="Y", periods=3)
          with pytest.raises(OutOfBoundsDatetime):
              pi.to_timestamp()
  
          with pytest.raises(OutOfBoundsDatetime):
              pi._data.to_timestamp()
  
      @pytest.mark.parametrize("propname", PeriodArray._bool_ops)
      def test_bool_properties(self, period_index, propname):
          # in this case _bool_ops is just `is_leap_year`
          pi = period_index
          arr = PeriodArray(pi)
  
          result = getattr(arr, propname)
          expected = np.array(getattr(pi, propname))
  
          tm.assert_numpy_array_equal(result, expected)
  
      @pytest.mark.parametrize("propname", PeriodArray._field_ops)
      def test_int_properties(self, period_index, propname):
          pi = period_index
          arr = PeriodArray(pi)
  
          result = getattr(arr, propname)
          expected = np.array(getattr(pi, propname))
  
          tm.assert_numpy_array_equal(result, expected)
  
      def test_array_interface(self, period_index):
          arr = PeriodArray(period_index)
  
          # default asarray gives objects
          result = np.asarray(arr)
          expected = np.array(list(arr), dtype=object)
          tm.assert_numpy_array_equal(result, expected)
  
          # to object dtype (same as default)
          result = np.asarray(arr, dtype=object)
          tm.assert_numpy_array_equal(result, expected)
  
          # to other dtypes
          with pytest.raises(TypeError):
              np.asarray(arr, dtype="int64")
  
          with pytest.raises(TypeError):
              np.asarray(arr, dtype="float64")
  
          result = np.asarray(arr, dtype="S20")
          expected = np.asarray(arr).astype("S20")
          tm.assert_numpy_array_equal(result, expected)
  
      def test_strftime(self, period_index):
          arr = PeriodArray(period_index)
  
          result = arr.strftime("%Y")
          expected = np.array([per.strftime("%Y") for per in arr], dtype=object)
          tm.assert_numpy_array_equal(result, expected)
  
      def test_strftime_nat(self):
          # GH 29578
          arr = PeriodArray(PeriodIndex(["2019-01-01", pd.NaT], dtype="period[D]"))
  
          result = arr.strftime("%Y-%m-%d")
          expected = np.array(["2019-01-01", np.nan], dtype=object)
          tm.assert_numpy_array_equal(result, expected)
  
  
  @pytest.mark.parametrize(
      "array,casting_nats",
      [
          (
              pd.TimedeltaIndex(["1 Day", "3 Hours", "NaT"])._data,
              (pd.NaT, np.timedelta64("NaT", "ns")),
          ),
          (
              pd.date_range("2000-01-01", periods=3, freq="D")._data,
              (pd.NaT, np.datetime64("NaT", "ns")),
          ),
          (pd.period_range("2000-01-01", periods=3, freq="D")._data, (pd.NaT,)),
      ],
      ids=lambda x: type(x).__name__,
  )
  def test_casting_nat_setitem_array(array, casting_nats):
      expected = type(array)._from_sequence([pd.NaT, array[1], array[2]])
  
      for nat in casting_nats:
          arr = array.copy()
          arr[0] = nat
          tm.assert_equal(arr, expected)
  
  
  @pytest.mark.parametrize(
      "array,non_casting_nats",
      [
          (
              pd.TimedeltaIndex(["1 Day", "3 Hours", "NaT"])._data,
              (np.datetime64("NaT", "ns"), pd.NaT.value),
          ),
          (
              pd.date_range("2000-01-01", periods=3, freq="D")._data,
              (np.timedelta64("NaT", "ns"), pd.NaT.value),
          ),
          (
              pd.period_range("2000-01-01", periods=3, freq="D")._data,
              (np.datetime64("NaT", "ns"), np.timedelta64("NaT", "ns"), pd.NaT.value),
          ),
      ],
      ids=lambda x: type(x).__name__,
  )
  def test_invalid_nat_setitem_array(array, non_casting_nats):
      for nat in non_casting_nats:
          with pytest.raises(TypeError):
              array[0] = nat
  