text: import numpy as np
  import pytest
  
  from pandas import DataFrame, Index, MultiIndex, date_range
  import pandas._testing as tm
  
  
  class TestTZConvert:
      def test_frame_tz_convert(self):
          rng = date_range("1/1/2011", periods=200, freq="D", tz="US/Eastern")
  
          df = DataFrame({"a": 1}, index=rng)
          result = df.tz_convert("Europe/Berlin")
          expected = DataFrame({"a": 1}, rng.tz_convert("Europe/Berlin"))
          assert result.index.tz.zone == "Europe/Berlin"
          tm.assert_frame_equal(result, expected)
  
          df = df.T
          result = df.tz_convert("Europe/Berlin", axis=1)
          assert result.columns.tz.zone == "Europe/Berlin"
          tm.assert_frame_equal(result, expected.T)
  
      @pytest.mark.parametrize("fn", ["tz_localize", "tz_convert"])
      def test_tz_convert_and_localize(self, fn):
          l0 = date_range("20140701", periods=5, freq="D")
          l1 = date_range("20140701", periods=5, freq="D")
  
          int_idx = Index(range(5))
  
          if fn == "tz_convert":
              l0 = l0.tz_localize("UTC")
              l1 = l1.tz_localize("UTC")
  
          for idx in [l0, l1]:
  
              l0_expected = getattr(idx, fn)("US/Pacific")
              l1_expected = getattr(idx, fn)("US/Pacific")
  
              df1 = DataFrame(np.ones(5), index=l0)
              df1 = getattr(df1, fn)("US/Pacific")
              tm.assert_index_equal(df1.index, l0_expected)
  
              # MultiIndex
              # GH7846
              df2 = DataFrame(np.ones(5), MultiIndex.from_arrays([l0, l1]))
  
              # freq is not preserved in MultiIndex construction
              l1_expected = l1_expected._with_freq(None)
              l0_expected = l0_expected._with_freq(None)
              l1 = l1._with_freq(None)
              l0 = l0._with_freq(None)
  
              df3 = getattr(df2, fn)("US/Pacific", level=0)
              assert not df3.index.levels[0].equals(l0)
              tm.assert_index_equal(df3.index.levels[0], l0_expected)
              tm.assert_index_equal(df3.index.levels[1], l1)
              assert not df3.index.levels[1].equals(l1_expected)
  
              df3 = getattr(df2, fn)("US/Pacific", level=1)
              tm.assert_index_equal(df3.index.levels[0], l0)
              assert not df3.index.levels[0].equals(l0_expected)
              tm.assert_index_equal(df3.index.levels[1], l1_expected)
              assert not df3.index.levels[1].equals(l1)
  
              df4 = DataFrame(np.ones(5), MultiIndex.from_arrays([int_idx, l0]))
  
              # TODO: untested
              df5 = getattr(df4, fn)("US/Pacific", level=1)  # noqa
  
              tm.assert_index_equal(df3.index.levels[0], l0)
              assert not df3.index.levels[0].equals(l0_expected)
              tm.assert_index_equal(df3.index.levels[1], l1_expected)
              assert not df3.index.levels[1].equals(l1)
  
          # Bad Inputs
  
          # Not DatetimeIndex / PeriodIndex
          with pytest.raises(TypeError, match="DatetimeIndex"):
              df = DataFrame(index=int_idx)
              df = getattr(df, fn)("US/Pacific")
  
          # Not DatetimeIndex / PeriodIndex
          with pytest.raises(TypeError, match="DatetimeIndex"):
              df = DataFrame(np.ones(5), MultiIndex.from_arrays([int_idx, l0]))
              df = getattr(df, fn)("US/Pacific", level=0)
  
          # Invalid level
          with pytest.raises(ValueError, match="not valid"):
              df = DataFrame(index=l0)
              df = getattr(df, fn)("US/Pacific", level=1)
  