users.add(getUser("test3", 0.4, 0.4, 0.5, 0.9));
users.add(getUser("test4"));
DataModel dataModel = new GenericDataModel(users);
UserSimilarity similarity = new PearsonCorrelationSimilarity(dataModel);
UserNeighborhood neighborhood = new NearestNUserNeighborhood(3, similarity, dataModel);
UserBasedRecommender recommender = new GenericUserBasedRecommender(dataModel, neighborhood, similarity);
Collection<User> mostSimilar = recommender.mostSimilarUsers("test4", 3);
assertNotNull(mostSimilar);
assertEquals(0, mostSimilar.size());
}