code: def test_fillna_series_empty_arg(using_copy_on_write):
      ser = Series([1, np.nan, 2])
      ser_orig = ser.copy()
      result = ser.fillna({})
  
      if using_copy_on_write:
          assert np.shares_memory(get_array(ser), get_array(result))
      else:
          assert not np.shares_memory(get_array(ser), get_array(result))
  
      ser.iloc[0] = 100.5
      tm.assert_series_equal(ser_orig, result)
  
imports: import numpy
  import pytest
  from pandas import NA, ArrowDtype, DataFrame, Interval, NaT, Series, Timestamp, interval_range, option_context
  import pandas._testing
  from pandas.tests.copy_view.util import get_array
label_desc: Use image node_id 17 for calling a global function with example usage: test_fillna_series_empty_arg(using_copy_on_write) without return types