* first decrementing to zero, and then removing. putIfAbsent or replace could observe the
   * intermediate zero-state. Ways we could deal with this are:
   *
   * - Don't define any of the ConcurrentMap operations. This is the current state of affairs.
   *
   * - Define putIfAbsent and replace as treating zero and absent identically (as currently

  }

  @CollectionSize.Require(ZERO)
  public void testEmptyMapFirst() {
    assertNull(navigableMap.firstEntry());
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)
  public void testEmptyMapPollFirst() {
    assertNull(navigableMap.pollFirstEntry());
  }

  @CollectionSize.Require(ZERO)
  public void testEmptyMapNearby() {

import static com.google.common.collect.testing.features.CollectionSize.ONE;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEY_QUERIES;

    }
    assertEquals(expectedSize, size2);
  }

  @CollectionSize.Require(ZERO)
  public void testIsEmptyYes() {
    assertTrue(multimap().isEmpty());
  }

  @CollectionSize.Require(absent = ZERO)
  public void testIsEmptyNo() {
    assertFalse(multimap().isEmpty());
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(ALLOWS_NULL_KEYS)
  public void testSizeNullKey() {

    }
    assertEquals(expectedSize, size2);
  }

  @CollectionSize.Require(ZERO)
  public void testIsEmptyYes() {
    assertTrue(multimap().isEmpty());
  }

  @CollectionSize.Require(absent = ZERO)
  public void testIsEmptyNo() {
    assertFalse(multimap().isEmpty());
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(ALLOWS_NULL_KEYS)
  public void testSizeNullKey() {

  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemovePresent() {
    assertTrue(multimap().remove(k0(), v0()));

    assertFalse(multimap().containsEntry(k0(), v0()));
    expectMissing(e0());
    assertEquals(getNumElements() - 1, multimap().size());
    assertGet(k0(), ImmutableList.<V>of());
  }

  @CollectionSize.Require(absent = ZERO)

  @CollectionFeature.Require(SUPPORTS_ADD)
  @CollectionSize.Require(absent = ZERO)
  public void testAdd_supportedPresent() {
    assertTrue("add(present) should return true", getList().add(e0()));
    expectAdded(e0());
  }

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

      if (entries.size() >= 3) {
        c = entries.get(2);
      }
    }
  }

  @CollectionSize.Require(ZERO)
  public void testEmptyMapFirst() {
    try {
      navigableMap.firstKey();
      fail();
    } catch (NoSuchElementException e) {
    }
  }

  @CollectionSize.Require(ZERO)
  public void testEmptyMapLast() {
    try {
      assertNull(navigableMap.lastKey());
      fail();

  @CollectionSize.Require(ZERO)
  public void testPutPresentKeyDifferentValue() {
    getMap().put(k0(), v0());
    getMap().put(k0(), v1());
    // verify that the bimap is changed, and that the old inverse mapping
    // from v1 -> v0 is deleted
    expectContents(Helpers.mapEntry(k0(), v1()));
  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(ZERO)
  public void putDistinctKeysDistinctValues() {

import static com.google.common.collect.testing.Helpers.assertEmpty;
import static com.google.common.collect.testing.Helpers.assertEqualIgnoringOrder;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_VALUES;