def test_keys_may_be_added_previous_state_specified_by_none(self):
change = [{'from': {'new_key': None}, 'to': {'new_key': 'qweert'}}]
tags = apply_changes({'key': 'value'}, change)
self.assertEqual({'key': 'value', 'new_key': 'qweert'}, tags)
def test_for_apply_changes_function_presence(self):
tags = {}
change = {}
apply_changes(tags, change)
def test_keys_may_be_added_to_empty_object(self):
change = [{'from': {}, 'to': {'new_key': 'qweert'}}]
tags = apply_changes({}, change)
self.assertEqual({'new_key': 'qweert'}, tags)
def test_keys_may_be_added(self):
change = [{'from': {}, 'to': {'new_key': 'qweert'}}]
tags = apply_changes({'key': 'value'}, change)
self.assertEqual({'key': 'value', 'new_key': 'qweert'}, tags)
def test_from_values_are_deleted_on_specifying_none(self):
change = [{'from': {'key': 'value'}, 'to': {'key': None}}]
tags = apply_changes({'key': 'value'}, change)
self.assertEqual({}, tags)
def test_from_values_are_deleted(self):
change = [{'from': {'key': 'value'}, 'to': {}}]
tags = apply_changes({'key': 'value'}, change)
self.assertEqual({}, tags)
def test_simplest_applying_changes(self):
tags = {'wikipedia': 'en:Walmart Market'}
change = [{'to': {'wikipedia': 'en:Walmart'}, 'from': {'wikipedia': 'en:Walmart Market'}}]
tags = apply_changes(tags, change)
self.assertEqual({"wikipedia": "en:Walmart"}, tags)