@Test
public void testMostSimilar() throws Exception {

  ItemBasedRecommender recommender = buildRecommender();
  List<RecommendedItem> similar = recommender.mostSimilarItems(0, 2);
  assertNotNull(similar);
  assertEquals(2, similar.size());
  RecommendedItem first = similar.get(0);
  RecommendedItem second = similar.get(1);
  assertEquals(1, first.getItemID());
  assertEquals(1.0f, first.getValue(), EPSILON);
  assertEquals(2, second.getItemID());
  assertEquals(0.5f, second.getValue(), EPSILON);
}