code: def test_fillna_no_op_returns_copy(self, data):
      data = data[~data.isna()]
  
      valid = data[0]
      result = data.fillna(valid)
      assert result is not data
      tm.assert_extension_array_equal(result, data)
  
      result = data._pad_or_backfill(method="backfill")
      assert result is not data
      tm.assert_extension_array_equal(result, data)
  
file_path: pandas/pandas/tests/extension/base/missing.py
imports: import numpy
  import pytest
  import pandas
  import pandas._testing
label_desc: Use image node_id 10 for calling the BaseMissingTests obj's underlying member method code with example usage: obj.test_fillna_no_op_returns_copy(data) without return types