code: def binary_op_like_einsum_test_data(self):
      smoke_data = [
          dict(
              func_name="matvec",
              a=rand(3, 3),
              b=rand(3),
              einsum_expr="ij,j->i",
          )
      ]
      return self.generate_tests(smoke_data)
  
imports: import geomstats.backend
  from geomstats.test.data import TestData
label_desc: Use image node_id 1 for calling the AgainstEinsumTestData obj's underlying member method code with example usage: obj.binary_op_like_einsum_test_data() and returns: self