}

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  public void testFind_nullNotContainedButSupported() {
    assertEquals(getMethodName() + "(nullNotPresent) should return -1", -1, find(null));
  }

  @CollectionFeature.Require(absent = ALLOWS_NULL_VALUES)
  public void testFind_nullNotContainedAndUnsupported() {
    try {

  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_VALUES})
  public void testPutAllNullValueOnPresentKey_supported() {
    assertTrue(multimap().putAll(k0(), newArrayList(v3(), null)));
    assertGet(k0(), v0(), v3(), null);
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_VALUES})
  public void testPutAllNullValueOnAbsentKey_supported() {

    expectAdded(e3());
  }

  @CollectionFeature.Require({SUPPORTS_ADD, ALLOWS_NULL_VALUES})
  public void testOffer_nullSupported() {
    assertTrue("offer(null) should return true", getQueue().offer(null));
    expectAdded((E) null);
  }

  @CollectionFeature.Require(value = SUPPORTS_ADD, absent = ALLOWS_NULL_VALUES)
  public void testOffer_nullUnsupported() {

  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testContains_nonNullWhenNullContained() {
    initCollectionWithNullElement();
    assertFalse("contains(notPresent) should return false", collection.contains(e3()));
  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)

  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_VALUES})
  public void testPut_nullValueSupported() {
    assertNull("put(key, null) should return null", put(nullValueEntry));
    expectAdded(nullValueEntry);
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_VALUES)
  public void testPut_nullValueUnsupported() {

  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(ALLOWS_NULL_VALUES)
  public void testSizeNullValue() {
    initMultimapWithNullValue();
    assertEquals(getNumElements(), multimap().size());
    assertFalse(multimap().isEmpty());
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require({ALLOWS_NULL_KEYS, ALLOWS_NULL_VALUES})
  public void testSizeNullKeyAndValue() {

                return singleton(elements[0]);
              }
            })
        .named("singleton")
        .withFeatures(
            CollectionFeature.SERIALIZABLE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionSize.ONE)
        .suppressing(suppressForSingletonSet())
        .createTestSuite();
  }

  public Test testsForHashSet() {
    return SetTestSuiteBuilder.using(

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  public void testSetCount_removeNull_nullSupported() {
    initCollectionWithNullElement();
    assertSetCount(null, 0);
  }

  @CollectionFeature.Require(
      value = {SUPPORTS_ADD, ALLOWS_NULL_VALUES},
      absent = RESTRICTS_ELEMENTS)
  public void testSetCount_addNull_nullSupported() {

            .withFeatures(CollectionSize.ANY, CollectionFeature.ALLOWS_NULL_VALUES)
            .named("Multisets.union")
            .createTestSuite());

    suite.addTest(
        MultisetTestSuiteBuilder.using(intersectionGenerator())
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.ALLOWS_NULL_VALUES,
                CollectionFeature.KNOWN_ORDER)

  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  public void testAddAtIndex_nullSupported() {
    getList().add(0, null);
    expectAdded(0, (E) null);
  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  @CollectionFeature.Require(absent = ALLOWS_NULL_VALUES)
  public void testAddAtIndex_nullUnsupported() {