code: def test_method(self):
      data = pd.Series([2, np.nan, 15, 3, np.nan, 4.5])
      answer = pd.Series([np.nan, 13, 0, 12, 1.5, 0])
      primitive_func = AbsoluteDiff(method="backfill").get_function()
      given_answer = primitive_func(data)
      np.testing.assert_array_equal(given_answer, answer)
  
file_path: featuretools/featuretools/tests/primitive_tests/test_absolute_diff.py
imports: import numpy
  import pandas
  import pytest
  from featuretools.primitives import AbsoluteDiff
label_desc: Use image node_id 3 for calling the TestAbsoluteDiff obj's underlying member method code with example usage: obj.test_method() without return types