Test operators
==============

  >>> from shapely.geometry import Point
  >>> point = Point(0, 0)
  >>> point2 = Point(-1, 1)

  >>> point.union(point2).equals(point | point2)
  True

  >>> (point & point2).is_empty
  True

  >>> point.equals(point - point2)
  True

  >>> point.symmetric_difference(point2).equals(point ^ point2)
  True
