def test_transform_user_without_user_bias():
user = 12
algo = Bias()
algo.fit(simple_df)
new_ratings = pd.Series([-0.5, 1.5], index=[2, 3]) # items as index and ratings as values
v = algo.inverse_transform_user(user, new_ratings)
assert v[2] == new_ratings[2] + algo.user_offsets_.loc[user] + algo.item_offsets_.loc[2] + algo.mean_
assert v[3] == new_ratings[3] + algo.user_offsets_.loc[user] + algo.item_offsets_.loc[3] + algo.mean_
def test_transform_user_with_user_bias():
algo = Bias()
algo.fit(simple_df)
new_ratings = pd.Series([4.0, 5.0], index=[1, 2]) # items as index and ratings as values
ratings_with_bias, user_bias = algo.transform_user(new_ratings) # user: 13
result = algo.inverse_transform_user(13, ratings_with_bias, user_bias)
assert new_ratings[1] == result[1]
assert new_ratings[2] == result[2]