new_contents: # -*- coding: utf-8 -*-
  #
  # Copyright 2012-2015 Spotify AB
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  # http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  #
  
  from helpers import unittest, in_parse
  
  import luigi
  import luigi.interface
  import json
  import collections
  
  
  class DictParameterTask(luigi.Task):
      param = luigi.DictParameter()
  
  
  class DictParameterTest(unittest.TestCase):
  
      _dict = collections.OrderedDict([('username', 'me'), ('password', 'secret')])
  
      def test_parse(self):
          d = luigi.DictParameter().parse(json.dumps(DictParameterTest._dict))
          self.assertEqual(d, DictParameterTest._dict)
  
      def test_serialize(self):
          d = luigi.DictParameter().serialize(DictParameterTest._dict)
          self.assertEqual(d, '{"username": "me", "password": "secret"}')
  
      def test_parse_interface(self):
          in_parse(["DictParameterTask", "--param", '{"username": "me", "password": "secret"}'],
                   lambda task: self.assertEqual(task.param, DictParameterTest._dict))
  
      def test_serialize_task(self):
          t = DictParameterTask(DictParameterTest._dict)
          self.assertEqual(str(t), 'DictParameterTask(param={"username": "me", "password": "secret"})')
  
      def test_parse_invalid_input(self):
          self.assertRaises(ValueError, lambda: luigi.DictParameter().parse('{"invalid"}'))
  
subject: Add test cases for DictParameter