content: /**
   * Copyright (c) 2019, the Alpha Team.
   * All rights reserved.
   *
   * Additional changes made by Siemens.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * 1) Redistributions of source code must retain the above copyright notice, this
   *    list of conditions and the following disclaimer.
   *
   * 2) Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  package at.ac.tuwien.kr.alpha.core.solver;
  
  import static at.ac.tuwien.kr.alpha.core.common.NoGoodTest.fromOldLiterals;
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertNull;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  import at.ac.tuwien.kr.alpha.core.common.AtomStore;
  import at.ac.tuwien.kr.alpha.core.common.AtomStoreImpl;
  import at.ac.tuwien.kr.alpha.core.common.NoGood;
  import at.ac.tuwien.kr.alpha.core.common.NoGoodInterface.Type;
  import at.ac.tuwien.kr.alpha.core.test.util.TestUtils;
  
  public class LearnedNoGoodDeletionTest {
  
  	private NoGoodStoreAlphaRoaming store;
  	private LearnedNoGoodDeletion learnedNoGoodDeletion;
  
  	public LearnedNoGoodDeletionTest() {
  		AtomStore atomStore = new AtomStoreImpl();
  		TestUtils.fillAtomStore(atomStore, 200);
  		WritableAssignment assignment = new TrailAssignment(atomStore);
  		assignment.growForMaxAtomId();
  		store = new NoGoodStoreAlphaRoaming(assignment);
  		learnedNoGoodDeletion = store.getLearnedNoGoodDeletion();
  	}
  
  	@BeforeEach
  	public void setUp() {
  		store.clear();
  		store.growForMaxAtomId(fromOldLiterals(200));
  		assertNull(store.add(1, new NoGood(fromOldLiterals(1, -2))));
  		assertNull(store.add(2, new NoGood(fromOldLiterals(2, -3))));
  		assertNull(store.add(3, new NoGood(fromOldLiterals(2, -4, -5))));
  		assertNull(store.add(4, new NoGood(fromOldLiterals(3, 4, 5))));
  		assertNull(store.propagate());
  	}
  
  	@Test
  	public void testDeletionRunningAfterConflicts() {
  		for (int i = 0; i < LearnedNoGoodDeletion.RUN_AFTER_AT_LEAST; i++) {
  			learnedNoGoodDeletion.increaseConflictCounter();
  		}
  		assertFalse(learnedNoGoodDeletion.needToRunNoGoodDeletion());
  		learnedNoGoodDeletion.increaseConflictCounter();
  		assertTrue(learnedNoGoodDeletion.needToRunNoGoodDeletion());
  		learnedNoGoodDeletion.runNoGoodDeletion();
  		assertFalse(learnedNoGoodDeletion.needToRunNoGoodDeletion());
  	}
  
  	@Test
  	public void testDeletionRemovingWatches() {
  		for (int i = 0; i < LearnedNoGoodDeletion.RUN_AFTER_AT_LEAST; i++) {
  			learnedNoGoodDeletion.increaseConflictCounter();
  		}
  		assertFalse(learnedNoGoodDeletion.needToRunNoGoodDeletion());
  		learnedNoGoodDeletion.increaseConflictCounter();
  		assertTrue(learnedNoGoodDeletion.needToRunNoGoodDeletion());
  		assertNull(store.add(4, NoGood.learnt(fromOldLiterals(10, 11, 12)), 3));
  		assertNull(store.add(5, NoGood.learnt(fromOldLiterals(10, -13, -14)), 4));
  		List<WatchedNoGood> watchedNoGoods = learnedNoGoodDeletion.inspectLearnedNoGoods();
  		assertTrue(watchedNoGoods.size() >= 2);
  		WatchedNoGood watchedNoGood = watchedNoGoods.get(0);
  		for (int i = 0; i < 10; i++) {
  			watchedNoGood.bumpActivity();
  		}
  		learnedNoGoodDeletion.runNoGoodDeletion();
  		watchedNoGoods = learnedNoGoodDeletion.inspectLearnedNoGoods();
  		assertTrue(watchedNoGoods.size() < 2);
  	}
  
  	@Test
  	public void testDeletionIncreasesDeletionCounter() {
  		for (int i = 0; i < LearnedNoGoodDeletion.RUN_AFTER_AT_LEAST; i++) {
  			learnedNoGoodDeletion.increaseConflictCounter();
  		}
  		assertFalse(learnedNoGoodDeletion.needToRunNoGoodDeletion());
  		learnedNoGoodDeletion.increaseConflictCounter();
  		assertTrue(learnedNoGoodDeletion.needToRunNoGoodDeletion());
  		assertNull(store.add(4, NoGood.learnt(fromOldLiterals(10, 11, 12)), 3));
  		assertNull(store.add(5, NoGood.learnt(fromOldLiterals(10, -13, -14)), 4));
  		assertEquals(0, learnedNoGoodDeletion.getNumberOfDeletedNoGoods());
  		learnedNoGoodDeletion.runNoGoodDeletion();
  		assertTrue(learnedNoGoodDeletion.getNumberOfDeletedNoGoods() > 0);
  	}
  
  	@Test
  	public void testDeletionReducesNumberOfLearntNoGoods() {
  		for (int i = 0; i < LearnedNoGoodDeletion.RUN_AFTER_AT_LEAST; i++) {
  			learnedNoGoodDeletion.increaseConflictCounter();
  		}
  		assertFalse(learnedNoGoodDeletion.needToRunNoGoodDeletion());
  		learnedNoGoodDeletion.increaseConflictCounter();
  		assertTrue(learnedNoGoodDeletion.needToRunNoGoodDeletion());
  		assertNull(store.add(4, NoGood.learnt(fromOldLiterals(10, 11, 12)), 3));
  		assertNull(store.add(5, NoGood.learnt(fromOldLiterals(10, -13, -14)), 4));
  
  		final Map<Type, Integer> countersBeforeDeletion = countNoGoodsByType(store);
  		learnedNoGoodDeletion.runNoGoodDeletion();
  		final Map<Type, Integer> countersAfterDeletion = countNoGoodsByType(store);
  
  		for (Type type : Type.values()) {
  			if (type == Type.LEARNT) {
  				assertTrue(countersBeforeDeletion.get(type) > countersAfterDeletion.get(type), "Count of LEARNT nogoods did not decrease during deletion");
  			} else {
  				assertEquals(countersBeforeDeletion.get(type), countersAfterDeletion.get(type), "Unexpected count of " + type + " nogoods");
  			}
  		}
  
  	}
  
  	private Map<Type, Integer> countNoGoodsByType(NoGoodStore store) {
  		final Map<Type, Integer> counters = new HashMap<>();
  		final NoGoodCounter noGoodCounter = store.getNoGoodCounter();
  		for (Type type : Type.values()) {
  			counters.put(type, noGoodCounter.getNumberOfNoGoods(type));
  		}
  		return counters;
  	}
  }
  