old_contents: from .common import *
  from av.format import ContainerFormat, names
  
  
  class TestContainerFormats(TestCase):
  
      def test_matroska(self):
          fmt = ContainerFormat('matroska')
          self.assertTrue(fmt.is_input)
          self.assertTrue(fmt.is_output)
          self.assertEqual(fmt.name, 'matroska')
          self.assertEqual(fmt.long_name, 'Matroska')
          self.assertEqual(fmt.extensions, set(('mkv', )))
  
      def test_mov(self):
          fmt = ContainerFormat('mov')
          self.assertTrue(fmt.is_input)
          self.assertTrue(fmt.is_output)
          self.assertEqual(fmt.name, 'mov')
          self.assertEqual(fmt.long_name, 'QuickTime / MOV')
  
  
new_contents: from .common import *
  from av.format import ContainerFormat, names
  
  
  class TestContainerFormats(TestCase):
  
      def test_matroska(self):
          fmt = ContainerFormat('matroska')
          self.assertTrue(fmt.is_input)
          self.assertTrue(fmt.is_output)
          self.assertEqual(fmt.name, 'matroska')
          self.assertEqual(fmt.long_name, 'Matroska')
          self.assertIn('mkv', fmt.extensions)
  
      def test_mov(self):
          fmt = ContainerFormat('mov')
          self.assertTrue(fmt.is_input)
          self.assertTrue(fmt.is_output)
          self.assertEqual(fmt.name, 'mov')
          self.assertEqual(fmt.long_name, 'QuickTime / MOV')
  
  
subject: fix matroska test, other valid extensions are 'mks', 'mk3d', 'mka'