code: def test_read_simple_file(
      julia='''"""
     cube(x)
  
  Compute the cube of `x`, ``x^3``.
  
  # Examples
  ```jldoctest
  julia> cube(2)
  8
  ```
  """
  function cube(x)
     x^3
  end
  
  cube(x)
  
  # And a markdown comment
  ''',
  ):
      nb = jupytext.reads(julia, "jl")
      assert nb.metadata["jupytext"]["main_language"] == "julia"
      assert len(nb.cells) == 3
      assert nb.cells[0].cell_type == "code"
      assert (
          nb.cells[0].source
          == '''"""
     cube(x)
  
  Compute the cube of `x`, ``x^3``.
  
  # Examples
  ```jldoctest
  julia> cube(2)
  8
  ```
  """
  function cube(x)
     x^3
  end'''
      )
      assert nb.cells[1].cell_type == "code"
      assert nb.cells[1].source == "cube(x)"
      assert nb.cells[2].cell_type == "markdown"
      compare(nb.cells[2].source, "And a markdown comment")
  
      julia2 = jupytext.writes(nb, "jl")
      compare(julia2, julia)
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_read_simple_file(julia) without return types