code: def test_pipeline_one_node():
      pipeline = Pipeline(max_loops_allowed=10)
      pipeline.add_component("self_loop", SelfLoop())
      pipeline.connect("self_loop.current_value", "self_loop.values")
  
      results = pipeline.run({"self_loop": {"values": 5}})
      assert results["self_loop"]["final_result"] == 0
  
imports: from haystack.core.component import component
  from haystack.core.pipeline import Pipeline
  from haystack.testing.sample_components import AddFixedValue, SelfLoop
  import logging
label_desc: Use image node_id 1 for calling a global function with example usage: test_pipeline_one_node() without return types