docstr: Test the has_sindex method.
code: def test_has_sindex(self):
      """Test the has_sindex method."""
      t1 = Polygon([(0, 0), (1, 0), (1, 1)])
      t2 = Polygon([(0, 0), (1, 1), (0, 1)])
  
      d = GeoDataFrame({"geom": [t1, t2]}, geometry="geom")
      assert not d.has_sindex
      d.sindex
      assert d.has_sindex
      d.geometry.values._sindex = None
      assert not d.has_sindex
      d.sindex
      assert d.has_sindex
  
      s = GeoSeries([t1, t2])
      assert not s.has_sindex
      s.sindex
      assert s.has_sindex
      s.values._sindex = None
      assert not s.has_sindex
      s.sindex
      assert s.has_sindex
  
imports: from math import sqrt
  import numpy
  import pandas
  import pytest
  import shapely
  from numpy.testing import assert_array_equal
  from shapely.geometry import GeometryCollection, LineString, MultiPolygon, Point, Polygon, box
  import geopandas
  from geopandas import GeoDataFrame, GeoSeries, read_file
  from geopandas import _compat
label_desc: Use image node_id 1 for calling the TestSeriesSindex obj's underlying member method code with example usage: obj.test_has_sindex() without return types