code: def test_run_without_input():
      builder = PromptBuilder(
          template="This is a template without input"
      )
      res = builder.run()
      assert res == {"prompt": "This is a template without input"}
  
imports: import pytest
  from haystack.components.builders.prompt_builder import PromptBuilder
label_desc: Use image node_id 4 for calling a global function with example usage: test_run_without_input() without return types