text: import mock
  
  from docker_registry.lib import checksums
  from tests.base import TestCase
  
  
  class TestShaMethods(TestCase):
  
      def test_sha256_file(self):
          self.assertEqual(
              checksums.sha256_file(None, None),
              'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855')
          self.assertEqual(
              checksums.sha256_file(None, 'test'),
              '9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08')
  
      def test_compute_simple(self):
          out = checksums.compute_simple(None, '')
          self.assertTrue(out.startswith('sha256:'))
          nl = '01ba4719c80b6fe911b091a7c05124b64eeece964e09c058ef8f9805daca546b'
          self.assertTrue(out.endswith(nl))
  
          out = checksums.compute_simple(None, 'test')
          h = 'f2ca1bb6c7e907d06dafe4687e579fce76b37e4e93b7605022da52e6ccc26fd2'
          self.assertTrue(out.endswith(h))
  
  
  class TestTarSum(TestCase):
  
      def setUp(self):
          self.tar_sum = checksums.TarSum(None)
  
      def test_append(self):
          self.tar_sum.header_fields = tuple()
          member = mock.MagicMock(size=1)
          tarobj = mock.MagicMock(
              extractfile=mock.MagicMock(side_effect=KeyError))
          self.tar_sum.append(member, tarobj)
          self.assertEqual(len(self.tar_sum.hashes), 1)
          self.assertEqual(
              self.tar_sum.hashes[0],
              'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855')
  