@Test
public void testFile() throws Exception {

  UserSimilarity userSimilarity = new PearsonCorrelationSimilarity(model);
  UserNeighborhood neighborhood = new NearestNUserNeighborhood(3, userSimilarity, model);
  Recommender recommender = new GenericUserBasedRecommender(model, neighborhood, userSimilarity);
  assertEquals(1, recommender.recommend(123, 3).size());
  assertEquals(0, recommender.recommend(234, 3).size());
  assertEquals(1, recommender.recommend(345, 3).size());
  // Make sure this doesn't throw an exception
  model.refresh(null);
}