This was a straightforward test for a junior level position. The README.md estimated completion should take 45 minutes. Provided were class and function stubs to complete and several unit tests which StackExchange won't let me link to due to my reputation (they are reproduced below).
I'd love to offer belabored rationalizations of why I did what I did, but I'm sure no one's interested. I stripped most comments for brevity, but they can be found in the above links. Please tear it apart:
import functools class Campaign: # Prefer not to refactor this because I think comparison logic belongs elsewhere def __init__(self, name, bid_price, target_keywords): self.name = name self.bid_price = bid_price self.target_keywords = target_keywords def __repr__(self): return "<Campaign> {}".format(self.name) @functools.total_ordering class Score: def __init__(self, user_search_terms, campaign): self.user_search_terms = user_search_terms self.campaign = campaign def __repr__(self): return "<Score> Campaign: {}, Relevance: {}".format(self.campaign.name, self.value) def __eq__(self, other): self._except_if_terms_ne(other) if self.campaign.bid_price == other.campaign.bid_price: return self.value == other.value return False def __lt__(self, other): self._except_if_terms_ne(other) if self.value < other.value: return True if self.value == other.value: return self.campaign.bid_price < other.campaign.bid_price return False def _except_if_terms_ne(self, other): if self.user_search_terms != other.user_search_terms: raise ValueError("Cannot compare unequal user search terms.") @property def value(self): ust_set = set(self.user_search_terms) ctk_set = set(self.campaign.target_keywords) return len(ust_set.intersection(ctk_set)) def choose_best_campaign_for_user(user_search_terms, campaigns): """ The "best" campaign to serve is the one with the most search term matches. If two or more campaigns have the same number of matches then the one with the highest bid_price should be served. If two or more campaigns have the same number of matches and the same bid_price, then either one may be returned. """ best_score = max([ Score(user_search_terms, camp) for camp in campaigns ]) return best_score.campaign if best_score.value > 0 else None And to the extent that they're relevant, the tests:
import unittest from bidder import Campaign, Score, choose_best_campaign_for_user # Sample campaigns for testing - the apple_mac and apple_ios campaigns have one keyword # in common 'apple' apple_mac_campaign = Campaign( name="Apple Mac Products", bid_price=1.00, target_keywords=["apple", "macbook", "macbook pro", "imac", "power mac", "mavericks"], ) apple_ios_campaign = Campaign( name="Apple IOS Products", bid_price=1.50, target_keywords=["apple", "ipad", "iphone", "ios", "appstore", "siri"], ) google_android_campaign = Campaign( name="Google Android Products", bid_price=1.50, target_keywords=["google", "android", "phone"] ) marvel_comics_campaign = Campaign( name="Marvel Comics", bid_price=0.50, target_keywords=["spiderman", "hulk", "wolverine", "ironman", "captain america"], ) all_campaigns = [ apple_mac_campaign, apple_ios_campaign, marvel_comics_campaign ] class ScoreTest(unittest.TestCase): def setUp(self): self.eq_val_dif_bids = ( Score([], apple_mac_campaign), Score([], apple_ios_campaign) ) self.eq_val_eq_bid = ( Score([], apple_ios_campaign), Score([], google_android_campaign) ) def test_eq_val_eq_bid_compares_eq(self): self.assertEqual(self.eq_val_eq_bid[0], self.eq_val_eq_bid[1]) def test_eq_val_dif_bids_compares_lt(self): self.assertTrue(self.eq_val_dif_bids[0] < self.eq_val_dif_bids[1]) def test_nonidentical_search_terms_raise_value_error(self): with self.assertRaises(ValueError): Score([], apple_ios_campaign) == Score(["test"], google_android_campaign) class BidderTest(unittest.TestCase): def test_it_picks_no_campaign_if_no_keywords_match(self): chosen_campaign = choose_best_campaign_for_user( user_search_terms=["batman"], campaigns=[marvel_comics_campaign], ) self.assertIsNone(chosen_campaign) def test_it_chooses_a_campaign_if_search_terms_match_keywords(self): chosen_campaign = choose_best_campaign_for_user( user_search_terms=["spiderman"], campaigns=[marvel_comics_campaign], ) self.assertEqual(marvel_comics_campaign, chosen_campaign) def test_it_chooses_campaign_with_most_overlapping_keywords(self): chosen_campaign = choose_best_campaign_for_user( ["apple", "macbook"], all_campaigns ) self.assertEqual(chosen_campaign, apple_mac_campaign) def test_it_chooses_campaign_with_higher_bid_price(self): chosen_campaign = choose_best_campaign_for_user( ["apple"], all_campaigns ) self.assertEqual(chosen_campaign, apple_ios_campaign) if __name__ == "__main__": unittest.main() 
