code: def test_header_to_metadata_and_cell_no_blank_line():
      text = """---
  title: Sample header
  ---
  Header is not followed by a blank line
  """
      lines = text.splitlines()
      metadata, _, cell, pos = header_to_metadata_and_cell(
          lines, "", ""
      )
  
      assert metadata == {}
      assert cell.cell_type == "raw"
      assert (
          cell.source
          == """---
  title: Sample header
  ---"""
      )
      assert cell.metadata == {"lines_to_next_cell": 0}
      assert lines[pos].startswith("Header is")
  
file_path: jupytext/tests/unit/test_header.py
imports: from nbformat.v4.nbbase import new_markdown_cell, new_notebook, new_raw_cell
  import jupytext
  from jupytext.compare import compare
  from jupytext.formats import get_format_implementation
  from jupytext.header import header_to_metadata_and_cell, metadata_and_cell_to_header, uncomment_line
label_desc: Use image node_id 3 for calling a global function with example usage: test_header_to_metadata_and_cell_no_blank_line() without return types