class_docstr: Unit test for operator loader.
class_docstr_tok: ["Unit","test","for","operator","loader","."]
code: def test_op_name(self):
      op1 = ops.local.cal_sum(10)
      self.assertEqual(op1(10), 20)
      op2 = ops.local.cal_diff(10)
      self.assertEqual(op2(10), 0)
  
file_path: towhee/tests/unittests/runtime/test_operator_loader.py
imports: import unittest
  from ..None import operator_cache
  from towhee.runtime import ops
  from towhee.runtime.operator_manager.operator_loader import OperatorLoader
label_desc: Use image node_id 6 for calling the TestOperatorLoader obj's underlying member method code with example usage: obj.test_op_name() without return types