/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.mahout.cf.taste.impl.recommender;
import java.util.Collections;
import java.util.List;
import com.google.common.collect.Lists;
import org.apache.mahout.cf.taste.common.TasteException;
import org.apache.mahout.cf.taste.impl.TasteTestCase;
import org.apache.mahout.cf.taste.impl.common.FastIDSet;
import org.apache.mahout.cf.taste.impl.model.GenericItemPreferenceArray;
import org.apache.mahout.cf.taste.impl.model.GenericPreference;
import org.apache.mahout.cf.taste.impl.model.GenericUserPreferenceArray;
import org.apache.mahout.cf.taste.model.DataModel;
import org.apache.mahout.cf.taste.model.Preference;
import org.apache.mahout.cf.taste.model.PreferenceArray;
import org.apache.mahout.cf.taste.recommender.CandidateItemsStrategy;
import org.easymock.EasyMock;
import org.junit.Test;
/**
* Tests {@link PreferredItemsNeighborhoodCandidateItemsStrategy}
*/
public final class PreferredItemsNeighborhoodCandidateItemsStrategyTest extends TasteTestCase {
@Test
public void testStrategy() throws TasteException {
FastIDSet itemIDsFromUser123 = new FastIDSet();
itemIDsFromUser123.add(1L);
FastIDSet itemIDsFromUser456 = new FastIDSet();
itemIDsFromUser456.add(1L);
itemIDsFromUser456.add(2L);
List<Preference> prefs = Lists.newArrayList();
prefs.add(new GenericPreference(123L, 1L, 1.0f));
prefs.add(new GenericPreference(456L, 1L, 1.0f));
PreferenceArray preferencesForItem1 = new GenericItemPreferenceArray(prefs);
DataModel dataModel = EasyMock.createMock(DataModel.class);
EasyMock.expect(dataModel.getPreferencesForItem(1L)).andReturn(preferencesForItem1);
EasyMock.expect(dataModel.getItemIDsFromUser(123L)).andReturn(itemIDsFromUser123);
EasyMock.expect(dataModel.getItemIDsFromUser(456L)).andReturn(itemIDsFromUser456);
PreferenceArray prefArrayOfUser123 =
new GenericUserPreferenceArray(Collections.singletonList(new GenericPreference(123L, 1L, 1.0f)));
CandidateItemsStrategy strategy = new PreferredItemsNeighborhoodCandidateItemsStrategy();
EasyMock.replay(dataModel);
FastIDSet candidateItems = strategy.getCandidateItems(123L, prefArrayOfUser123, dataModel);
assertEquals(1, candidateItems.size());
assertTrue(candidateItems.contains(2L));
EasyMock.verify(dataModel);
}
}