class_docstr: Test RuntimePipeline in Pipeline
class_docstr_tok: ["Test","RuntimePipeline","in","Pipeline"]
code: def test_output(self):
      p_1 = (
          pipe.input("x", "y")
          .map(("x", "y"), "z", lambda x, y: x + y)
          .map("x", "y", lambda x: x + 1)
          .output("z")
      )
  
      p = pipe.input("x", "y").map(("x", "y"), "z", p_1).output("z")
      res = p(1, 2).get()
      self.assertEqual(res, [3])
  
file_path: towhee/tests/unittests/runtime/test_dag_pipeline.py
imports: import unittest
  from towhee import pipe
label_desc: Use image node_id 4 for calling the TestDAGPipeline obj's underlying member method code with example usage: obj.test_output() without return types