Synnefo » snf-ganeti

def JoinDisjointDicts(dict_a, dict_b):

  """Joins dictionaries with no conflicting keys.

  Enforces the constraint that the two key sets must be disjoint, and then

  merges the two dictionaries in a new dictionary that is returned to the

  caller.

  @type dict_a: dict

  @param dict_a: the first dictionary

  @type dict_b: dict

  @param dict_b: the second dictionary

  @rtype: dict

  @return: a new dictionary containing all the key/value pairs contained in the

  two dictionaries.

  """

  assert not (set(dict_a) & set(dict_b)), ("Duplicate keys found while joining"

                                           " %s and %s" % (dict_a, dict_b))

  result = dict_a.copy()

  result.update(dict_b)

  return result

class TestJoinDisjointDicts(unittest.TestCase):

  def setUp(self):

    self.non_empty_dict = {"a": 1, "b": 2}

    self.empty_dict = dict()

  def testWithEmptyDicts(self):

    self.assertEqual(self.empty_dict, algo.JoinDisjointDicts(self.empty_dict,

      self.empty_dict))

    self.assertEqual(self.non_empty_dict, algo.JoinDisjointDicts(

      self.empty_dict, self.non_empty_dict))

    self.assertEqual(self.non_empty_dict, algo.JoinDisjointDicts(

      self.non_empty_dict, self.empty_dict))

  def testNonDisjoint(self):

    self.assertRaises(AssertionError, algo.JoinDisjointDicts,

      self.non_empty_dict, self.non_empty_dict)

  def testCommonCase(self):

    dict_a = {"TEST1": 1, "TEST2": 2}

    dict_b = {"TEST3": 3, "TEST4": 4}

    result = dict_a.copy()

    result.update(dict_b)

    self.assertEqual(result, algo.JoinDisjointDicts(dict_a, dict_b))

    self.assertEqual(result, algo.JoinDisjointDicts(dict_b, dict_a))