code: def rotation_matrix_test_data(self):
      angle = 0.5
      data = [
          dict(
              theta=angle,
              expected=gs.array(
                  [
                      [gs.cos(angle), -gs.sin(angle)],
                      [gs.sin(angle), gs.cos(angle)],
                  ]
              ),
          )
      ]
      return self.generate_tests(data)
  
imports: import geomstats.backend
  from geomstats.algebra_utils import from_vector_to_diagonal_matrix
  from geomstats.test.data import TestData
label_desc: Use image node_id 7 for calling the LocalizationTestData obj's underlying member method code with example usage: obj.rotation_matrix_test_data() and returns: self