code: def metric_matrix_test_data(self):
      base_points = [
          gs.array([0.0, 0.0]),
          gs.array([1.0, 1.0]),
          gs.array([0.3, 0.8]),
      ]
      data = []
      for base_point in base_points:
          data.append(
              dict(
                  base_point=base_point,
                  expected=_expected_sphere_metric_matrix(base_point),
              )
          )
  
      return self.generate_tests(data)
  
imports: import geomstats.backend
  from geomstats.test.data import TestData
  from .riemannian_metric import RiemannianMetricComparisonTestData, RiemannianMetricTestData
label_desc: Use image node_id 1 for calling the SphereIntrinsicMetricTestData obj's underlying member method code with example usage: obj.metric_matrix_test_data() and returns: self