code: def test_shift_axis1_categorical_columns(self):
      # GH#38434
      ci = CategoricalIndex(["a", "b", "c"])
      df = DataFrame(
          {"a": [1, 3], "b": [2, 4], "c": [5, 6]},
          index=ci[:-1],
          columns=ci,
      )
      result = df.shift(axis=1)
  
      expected = DataFrame(
          {"a": [np.nan, np.nan], "b": [1, 3], "c": [2, 4]},
          index=ci[:-1],
          columns=ci,
      )
      tm.assert_frame_equal(result, expected)
  
      # periods != 1
      result = df.shift(2, axis=1)
      expected = DataFrame(
          {"a": [np.nan, np.nan], "b": [np.nan, np.nan], "c": [1, 3]},
          index=ci[:-1],
          columns=ci,
      )
      tm.assert_frame_equal(result, expected)
  
imports: import numpy
  import pytest
  import pandas
  from pandas import CategoricalIndex, DataFrame, Index, NaT, Series, date_range, offsets
  import pandas._testing
label_desc: Use image node_id 34 for calling the TestDataFrameShift obj's underlying member method code with example usage: obj.test_shift_axis1_categorical_columns() without return types