def test_fetch_news_items_raise_FeedReaderException(self):
# TODO: create a mock RssNewsFeedParser object and assign it to a local
# variable named `mock_news_feed_parser`
mock_news_feed_parser = Mock(spec=RssNewsFeedParser)
# TODO: configure the mock so that a call to its get_news() method has
# the side effect of raising a FeedReaderException.
mock_news_feed_parser.get_news.side_effect = FeedReaderException()
# TODO: create a FeedReader instance and assign it to a local variable
# named `feed_reader`
feed_reader = FeedReader()
# TODO: set the feed_reader.news_feed_parser attribute to
# mock_news_feed_parser
feed_reader.news_feed_parser = mock_news_feed_parser
# TODO: call the feed_reader's fetch_news_items() method and save the
# return value in a variable named `news`. (Pass any string as the
# argument to fetch_news_items())
news = feed_reader.fetch_news_items('quack')
# TODO: assert that the `news` variable is an instance of list.
self.assertTrue(isinstance(news, list))
# TODO: assert that the length of the `news` list is 0
self.assertEqual(0, len(news))
def test_fetch_news_items_music(self):
# TODO: create a mock RssNewsFeedParser object and assign it to a local
# variable named `mock_news_feed_parser`
mock_news_feed_parser = Mock(spec=RssNewsFeedParser)
# TODO: set the return value of the mock's get_news() method to the
# value of the variable `expected` (defined at the end of the file)
mock_news_feed_parser.get_news.return_value = expected
# TODO: create a FeedReader instance and assign it to a local variable
# named `feed_reader`
feed_reader = FeedReader()
# TODO: set the feed_reader.news_feed_parser attribute to the
# mock_news_feed_parser
feed_reader.news_feed_parser = mock_news_feed_parser
# TODO: note the call the call to feed_reader.fetch_news_items().
# Because you changed the feed reader's `news_feed_parser` attribute in
# the previous statement, the feed_reader will get news from the mock
# object instead of a RssNewsFeedParser instance.
# (no code change required)
news = feed_reader.fetch_news_items("music")
# TODO: note that we verify the result as usual.
# (no code change required)
for expected_result, actual_result in zip_longest(expected, news):
self.assertEqual(expected_result, actual_result)
def test_fetch_news_items_patch_decorator(self,
mock_news_feed_parser_class):
# Always patch an object where it is imported, not where it is defined.
# Here, we're testing a method in
# ticketmanor.rest_services.feed_reader.feed_reader.FeedReader, which
# imports RssNewsFeedParser. So to mock RssNewsFeedParser, patch()
# needs to know the package that is importing RssNewsFeedParser, not
# the package that defines RssNewsFeedParser.
# Note that the second argument to the test method is a
# Mock class, not a Mock instance, so we need an additional step
# to get a Mock instance for setting the get_news() return value.
mock_news_feed_parser = mock_news_feed_parser_class.return_value
mock_news_feed_parser.get_news.return_value = expected
feed_reader = FeedReader()
news = feed_reader.fetch_news_items("music", 2)
# verify that the mock's get_news() method was called correctly
# (for details, see Appendix B)
mock_news_feed_parser.get_news.assert_called_once_with("music", 2)
# verify results
for expected_result, actual_result in zip_longest(expected, news):
self.assertEqual(expected_result, actual_result)
def test_fetch_news_items_max_items_2(self):
# test set up
mock_news_feed_parser = Mock(spec=RssNewsFeedParser)
mock_news_feed_parser.get_news.return_value = expected
feed_reader = FeedReader()
feed_reader.news_feed_parser = mock_news_feed_parser
# call method under test
news = feed_reader.fetch_news_items("music", 2)
# verify that the mock's get_news() method was called correctly
# (for details, see Appendix B)
mock_news_feed_parser.get_news.assert_called_once_with("music", 2)
# verify results
for expected_result, actual_result in zip_longest(expected, news):
self.assertEqual(expected_result, actual_result)
def test_fetch_news_items_patch_object_decorator(self,
mock_get_news_method):
# Set the return value of the mocked method to the `expected`
# variable (defined at the end of the file)
mock_get_news_method.return_value = expected
# Note the call to the FeedReader constructor. The call to the
# RssNewsFeedParser will happen as usual, but because we added
# @patch.object to this test method, the RssNewsFeedParser's get_news
# attribute will be replaced by a Mock.
feed_reader = FeedReader()
# Note that the call to the feed_reader's fetch_news_items()
# will call the Mock's get_news(), which you programmed to return
# `expected`
news = feed_reader.fetch_news_items("music", 1)
# verify that the mock's get_news() method was called correctly
# (for details, see Appendix B)
mock_get_news_method.assert_called_once_with("music", 1)
# verify results
for expected_result, actual_result in zip_longest(expected, news):
self.assertEqual(expected_result, actual_result)
def setUp(self):
# The arg to FeedReader.__init__() is the class of the news feed
# parser. FeedReader will call the constructor of the news feed parser
# class, so we'll let it create a Mock, then we can access the Mock as
# an attribute of the feed parser.
self.feed_reader = FeedReader(news_feed_parser_class=Mock)
def __init__(self):
self.feed_reader = FeedReader()
