A `MagicMock` which maps dictionary methods to a sample dictionary.

dictionary_mock.py

def DictionaryMock(_sample_dict, methods=None):
    """ A mock dictionary.

        Makes it easier to check that the correct values are being retrieved
        from a dictionary.

        '_sample_dict': A dictionary of test values. Dictionary lookups will get
            values from this dictionary. """
    if methods is None:
        methods = [
        '__getitem__',
        '__setitem__',
        '__delitem__',
        '__iter__',
        '__len__',
        '__contains__',
        'keys',
        'values',
        'items',
        'get',
        'pop',
        'popitem',
        'clear',
        'update',
        'setdefault',
        ]

    mock_dict = MagicMock(*pargs, **kwargs)
    mock_dict._sample_dict = _sample_dict

    def make_side_effect(method_name):
        def side_effect(*pargs, **kwargs):
            sample_method = getattr(mock_dict._sample_dict, method_name)
            return sample_method(*pargs, **kwargs)
        return side_effect

    for method_name in methods:
        mock_method = getattr(mock_dict, method_name)
        mock_method.side_effect = make_side_effect(method_name)

    return mock_dict