code: def test_float_suffix(self):
      df = DataFrame(
          {
              "treatment_1.1": [1.0, 2.0],
              "treatment_2.1": [3.0, 4.0],
              "result_1.2": [5.0, 6.0],
              "result_1": [0, 9],
              "A": ["X1", "X2"],
          }
      )
      expected = DataFrame(
          {
              "A": ["X1", "X2", "X1", "X2", "X1", "X2", "X1", "X2"],
              "colname": [1.2, 1.2, 1.0, 1.0, 1.1, 1.1, 2.1, 2.1],
              "result": [
                  5.0,
                  6.0,
                  0.0,
                  9.0,
                  np.nan,
                  np.nan,
                  np.nan,
                  np.nan,
              ],
              "treatment": [
                  np.nan,
                  np.nan,
                  np.nan,
                  np.nan,
                  1.0,
                  2.0,
                  3.0,
                  4.0,
              ],
          }
      )
      expected = expected.set_index(["A", "colname"])
      result = wide_to_long(
          df,
          ["result", "treatment"],
          i="A",
          j="colname",
          suffix="[0-9.]+",
          sep="_",
      )
      tm.assert_frame_equal(result, expected)
  
imports: import re
  import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Index, date_range, lreshape, melt, wide_to_long
  import pandas._testing
label_desc: Use image node_id 16 for calling the TestWideToLong obj's underlying member method code with example usage: obj.test_float_suffix() without return types