old_contents: import os
  import os.path as osp
  from pathlib import Path
  
  import delegator
  
  # the helper modules for testing
  from myutils import (
      cd,
  )
  
  
  ## write one test per example
  
  # Lennard_Jones_Pair
  
  def test_lennard_jones_pair(datadir_factory, printer):
  
      example = "Lennard_Jones_Pair"
  
      datadir = datadir_factory.mkdatadir(f'../_examples/{example}')
  
      assert (datadir / "README.org").is_file()
      assert (datadir / "input").is_dir()
      assert (datadir / "source").is_dir()
  
  
      ##
  
      assert (datadir / "source/trivial_run.py").is_file()
  
      with cd(datadir):
          assert Path(os.getcwd()) == datadir
          proc = delegator.run([
              "python",
              "source/trivial_run.py",
          ])
  
      if not proc.ok:
          printer("Error for hello.py:")
          printer(proc.err)
  
      assert proc.ok
  
new_contents: import os
  import os.path as osp
  from pathlib import Path
  
  import delegator
  
  # the helper modules for testing
  from myutils import (
      cd,
  )
  
  
  ## write one test per example
  
  # Lennard_Jones_Pair
  
  def test_lennard_jones_pair(datadir_factory, printer):
  
      example = "Lennard_Jones_Pair"
  
      datadir = datadir_factory.mkdatadir(f'../_examples/{example}')
  
      assert (datadir / "README.org").is_file()
      assert (datadir / "input").is_dir()
      assert (datadir / "source").is_dir()
  
  
      ## trivial_run.py
  
      assert (datadir / "source/trivial_run.py").is_file()
  
      with cd(datadir):
          assert Path(os.getcwd()) == datadir
          proc = delegator.run([
              "python",
              "source/trivial_run.py",
          ])
  
      if not proc.ok:
          printer("Error for trivial_run.py:")
          printer(proc.err)
  
      assert proc.ok
  
subject: fix Lennard_Jones_Pair example test