old_contents: import os
  
  import nbgrader
  
  
  def test_nbextension():
      from nbgrader import _jupyter_nbextension_paths
      nbexts = _jupyter_nbextension_paths()
      assert len(nbexts) == 3
      assert nbexts[0]['section'] == 'tree'
      assert nbexts[1]['section'] == 'notebook'
      assert nbexts[2]['section'] == 'tree'
      paths = [ext['src'] for ext in nbexts]
      for path in paths:
          assert os.path.isdir(os.path.join(os.path.dirname(nbgrader.__file__), path))
  
  
  def test_serverextension():
      from nbgrader import _jupyter_server_extension_paths
      serverexts = _jupyter_server_extension_paths()
      assert len(serverexts) == 2
      assert serverexts[0]['module'] == 'nbgrader.server_extensions.assignment_list'
      assert serverexts[1]['module'] == 'nbgrader.server_extensions.formgrader'
  
new_contents: import os
  
  import nbgrader
  
  
  def test_nbextension():
      from nbgrader import _jupyter_nbextension_paths
      nbexts = _jupyter_nbextension_paths()
      assert len(nbexts) == 4
      assert nbexts[0]['section'] == 'tree'
      assert nbexts[1]['section'] == 'notebook'
      assert nbexts[2]['section'] == 'tree'
      assert nbexts[3]['section'] == 'notebook'
      paths = [ext['src'] for ext in nbexts]
      for path in paths:
          assert os.path.isdir(os.path.join(os.path.dirname(nbgrader.__file__), path))
  
  
  def test_serverextension():
      from nbgrader import _jupyter_server_extension_paths
      serverexts = _jupyter_server_extension_paths()
      assert len(serverexts) == 3
      assert serverexts[0]['module'] == 'nbgrader.server_extensions.assignment_list'
      assert serverexts[1]['module'] == 'nbgrader.server_extensions.formgrader'
      assert serverexts[2]['module'] == 'nbgrader.server_extensions.validate_assignment'
  
subject: Fix tests for nbgrader extensions