def test_add_normalized_rating(self):
"""Checks that the user average is substracted from all the ratings."""
ratings = self.get_ratings()
Builder.add_normalized_rating(ratings)
norm_ratings = ratings[ratings['userid'] == 3]
self.assertAlmostEqual(norm_ratings.iloc[0]['movieid'], 0)
self.assertAlmostEqual(norm_ratings.iloc[0]['normalized_rating'], 0.4)
self.assertAlmostEqual(norm_ratings.iloc[1]['movieid'], 2)
self.assertAlmostEqual(norm_ratings.iloc[1]['normalized_rating'], 0.4)
self.assertAlmostEqual(norm_ratings.iloc[2]['movieid'], 3)
self.assertAlmostEqual(norm_ratings.iloc[2]['normalized_rating'], 2.4)
self.assertAlmostEqual(norm_ratings.iloc[3]['movieid'], 4)
self.assertAlmostEqual(norm_ratings.iloc[3]['normalized_rating'], -1.6)
self.assertAlmostEqual(norm_ratings.iloc[4]['movieid'], 5)
self.assertAlmostEqual(norm_ratings.iloc[4]['normalized_rating'], -1.6)
