new_contents: """
  :Copyright: 2006-2020 Jochen Kupperschmidt
  :License: Modified BSD, see LICENSE for details.
  """
  
  import pytest
  
  from byceps.util.l10n import set_locale
  
  
  def test_set_locale_with_valid_locale():
      set_locale('en_US.utf8')
  
  
  def test_set_locale_with_invalid_locale():
      with pytest.warns(UserWarning) as record:
          set_locale('invalid')
  
      assert len(record) == 1
      assert record[0].message.args[0] == 'Could not set locale to "invalid".'
  
subject: Test `byceps.util.l10n.set_locale`