}

  // retainAll(empty)

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)
  public void testRetainAll_emptyPreviouslyEmpty() {
    expectReturnsFalse(empty);
    expectUnchanged();
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)
  public void testRetainAll_emptyPreviouslyEmptyUnsupported() {

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  @CollectionSize.Require(absent = ZERO)
  public void testAddAtIndex_supportedPresent() {
    getList().add(0, e0());
    expectAdded(0, e0());
  }

  @ListFeature.Require(absent = SUPPORTS_ADD_WITH_INDEX)
  @CollectionSize.Require(absent = ZERO)
  /*
   * absent = ZERO isn't required, since unmodList.add() must

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutAllNonEmptyIterableOnPresentKey() {
    assertTrue(multimap().putAll(k0(), newArrayList(v3(), v4())::iterator));
    assertGet(k0(), v0(), v3(), v4());
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutAllNonEmptyCollectionOnPresentKey() {

    } catch (UnsupportedOperationException tolerated) {
    }
  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testSetCount_oneToOne_addSupported() {
    assertOneToOne();
  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testSetCount_oneToOne_removeSupported() {
    assertOneToOne();
  }

  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testSpliteratorNullable() {
    initCollectionWithNullElement();
    assertFalse(collection.spliterator().hasCharacteristics(Spliterator.NONNULL));
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testSpliteratorNotImmutable_collectionAllowsAdd() {
    // If add is supported, verify that IMMUTABLE is not reported.

  }

  @CollectionFeature.Require(ALLOWS_NULL_QUERIES)
  public void testCount_nullAbsent() {
    assertEquals("multiset.count(null) didn't return 0", 0, getMultiset().count(null));
  }

  @CollectionFeature.Require(absent = ALLOWS_NULL_QUERIES)
  public void testCount_null_forbidden() {
    assertThrows(NullPointerException.class, () -> getMultiset().count(null));
  }

  @CollectionSize.Require(absent = ZERO)

    presentKeyNullValueEntry = entry(k0(), null);
  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testPut_supportedPresent() {
    assertEquals("put(present, value) should return the old value", v0(), getMap().put(k0(), v3()));
    expectReplacement(entry(k0(), v3()));
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPut_supportedNotPresent() {

    } catch (UnsupportedOperationException tolerated) {
    }
  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testSetCount_oneToOne_addSupported() {
    assertOneToOne();
  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testSetCount_oneToOne_removeSupported() {
    assertOneToOne();
  }

  @ListFeature.Require(SUPPORTS_SET)
  @CollectionSize.Require(absent = ZERO)
  public void testSet() {
    doTestSet(e3());
  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @ListFeature.Require(SUPPORTS_SET)
  public void testSet_null() {
    doTestSet(null);
  }

  @CollectionSize.Require(absent = ZERO)

public class MapPutIfAbsentTester<K, V> extends AbstractMapTester<K, V> {

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutIfAbsent_supportedAbsent() {
    assertNull(
        "putIfAbsent(notPresent, value) should return null", getMap().putIfAbsent(k3(), v3()));
    expectAdded(e3());
  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testPutIfAbsent_supportedPresent() {
    assertEquals(