message: NotebookTC: cwd independent
diff: +import os
  import unittest
  from tests.notebook_exec import run_notebook
  +ROOT = os.path.join(os.path.dirname(__file__), "..")
  +
  +
  class NotebookTC(unittest.TestCase):
  def test01_parse_and_dump(self):
  - _, errors = run_notebook('../notebooks/01_parse_and_dump.ipynb')
  + f = os.path.join(ROOT, 'notebooks', '01_parse_and_dump.ipynb')
  + _, errors = run_notebook(f)
  self.assertEqual(errors, [])
  