code: def test_ndarray_from_qpolygonf():
      # test that we get an empty ndarray from an empty QPolygonF
      poly = pg.functions.create_qpolygonf(0)
      arr = pg.functions.ndarray_from_qpolygonf(poly)
      assert isinstance(arr, np.ndarray)
  
imports: from collections import OrderedDict
  from copy import deepcopy
  import numpy
  import pytest
  from numpy.testing import assert_array_almost_equal
  import pyqtgraph
  from pyqtgraph.functions import arrayToQPath, eq
  from pyqtgraph.Qt import QtGui
label_desc: Use image node_id 12 for calling a global function with example usage: test_ndarray_from_qpolygonf() without return types