text: """Tests for nbformat.convert"""
  
  # Copyright (c) IPython Development Team.
  # Distributed under the terms of the Modified BSD License.
  
  from .base import TestsBase
  
  from ..converter import convert
  from ..reader import read, get_version
  from ..validator import isvalid, validate
  from .. import current_nbformat
  
  
  class TestConvert(TestsBase):
  
      def test_downgrade_3_2(self):
          """Do notebook downgrades work?"""
  
          # Open a version 3 notebook and attempt to downgrade it to version 2.
          with self.fopen(u'test3.ipynb', u'r') as f:
              nb = read(f)
          nb = convert(nb, 2)
  
          # Check if downgrade was successful.
          (major, minor) = get_version(nb)
          self.assertEqual(major, 2)
  
  
      def test_upgrade_2_3(self):
          """Do notebook upgrades work?"""
  
          # Open a version 2 notebook and attempt to upgrade it to version 3.
          with self.fopen(u'test2.ipynb', u'r') as f:
              nb = read(f)
          nb = convert(nb, 3)
  
          # Check if upgrade was successful.
          (major, minor) = get_version(nb)
          self.assertEqual(major, 3)
  
  
      def test_upgrade_downgrade_4_3_4(self):
          """Test that a v4 notebook downgraded to v3 and then upgraded to v4
          passes validation tests"""
          with self.fopen(u'test4.ipynb', u'r') as f:
              nb = read(f)
          validate(nb)
          nb = convert(nb, 3)
          validate(nb)
          nb = convert(nb, 4)
          self.assertEqual(isvalid(nb), True)
  
  
      def test_open_current(self):
          """Can an old notebook be opened and converted to the current version
          while remembering the original version of the notebook?"""
  
          # Open a version 2 notebook and attempt to upgrade it to the current version
          # while remembering it's version information.
          with self.fopen(u'test2.ipynb', u'r') as f:
              nb = read(f)
          (original_major, original_minor) = get_version(nb)
          nb = convert(nb, current_nbformat)
  
          # Check if upgrade was successful.
          (major, minor) = get_version(nb)
          self.assertEqual(major, current_nbformat)
  
          # Check if the original major revision was remembered.
          self.assertEqual(original_major, 2)
  