def METHOD_NAME(self):
    points = self.test_pts
    dsrc = XYDataSource(np.zeros((self.n, 2), dtype=int),
                        points=points, overwrite=True)
    to_add = [(8, 8**2), (9, 9**2)]
    dsrc.add_points(to_add)
    expected = np.array(points[len(to_add):] + to_add, dtype=int)
    actual = dsrc.get_points()
    assert_allclose(actual, expected)