@Test
public void testItemScorerChannels() {
long[] items = {7, 8};
ItemItemScorer scorer = session.get(ItemItemScorer.class);
assertThat(scorer, notNullValue());
SparseVector scores = scorer.score(5, LongArrayList.wrap(items));
assertThat(scores, notNullValue());
assertThat(scores.size(), equalTo(1));
assertThat(scores.get(7), not(notANumber()));
assertThat(scores.getChannelVector(ItemItemScorer.NEIGHBORHOOD_SIZE_SYMBOL).
get(7), closeTo(1.0, 1.0e-5));
assertThat(scores.containsKey(8), equalTo(false));
long[] items2 = {7, 8, 9};
scorer = session.get(ItemItemScorer.class);
assertThat(scorer, notNullValue());
scores = scorer.score(2, LongArrayList.wrap(items2));
assertThat(scores.getChannelVector(ItemItemScorer.NEIGHBORHOOD_SIZE_SYMBOL).
get(9), closeTo(3.0, 1.0e-5)); // 1, 7, 8
}