public void testContains_nonNullWhenNullContained() {
    initMapWithNullKey();
    assertFalse("containsKey(notPresent) should return false", getMap().containsKey(k3()));
  }

  @MapFeature.Require(ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)
  public void testContains_nullContained() {
    initMapWithNullKey();
    assertTrue("containsKey(null) should return true", getMap().containsKey(null));
  }

  @CollectionSize.Require(absent = ZERO)
  public void testGet_nonNullWhenNullContained() {
    initMapWithNullKey();
    assertNull("get(notPresent) should return null", get(k3()));
  }

  @MapFeature.Require(ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)
  public void testGet_nullContained() {
    initMapWithNullKey();
    assertEquals("get(null) should return the associated value", getValueForNullKey(), get(null));
  }

  public void testCreateWithNullKeySupported() {
    initMapWithNullKey();
    expectContents(createArrayWithNullKey());
  }

  @MapFeature.Require(absent = ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)
  public void testCreateWithNullKeyUnsupported() {
    assertThrows(NullPointerException.class, () -> initMapWithNullKey());
  }

  @MapFeature.Require(ALLOWS_NULL_VALUES)

  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(absent = NON_STANDARD_TOSTRING)
  @MapFeature.Require(ALLOWS_NULL_KEYS)
  public void testToStringWithNullKey() {
    initMapWithNullKey();
    testToString_formatting();
  }

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

  public void testGetOrDefault_nonNullWhenNullContained() {
    initMapWithNullKey();
    assertEquals(
        "getOrDefault(absent, default) should return default",
        v3(),
        getMap().getOrDefault(k3(), v3()));
  }

  @MapFeature.Require(ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)
  public void testGetOrDefault_presentNull() {
    initMapWithNullKey();
    assertEquals(

  public void testCreateWithNullKeySupported() {
    initMapWithNullKey();
    expectContents(createArrayWithNullKey());
  }

  @MapFeature.Require(absent = ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)
  public void testCreateWithNullKeyUnsupported() {
    assertThrows(NullPointerException.class, () -> initMapWithNullKey());
  }

  @MapFeature.Require(ALLOWS_NULL_VALUES)

    expectUnchanged();
  }

  @MapFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_KEYS})
  @CollectionSize.Require(absent = ZERO)
  public void testRemove_nullPresent() {
    initMapWithNullKey();

    int initialSize = getMap().size();
    assertEquals(
        "remove(null) should return the associated value",
        getValueForNullKey(),
        getMap().remove(null));
    assertEquals(

  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_KEYS})
  @CollectionSize.Require(absent = ZERO)
  public void testPut_nullKeySupportedPresent() {
    Entry<K, V> newEntry = entry(null, v3());
    initMapWithNullKey();
    assertEquals(
        "put(present, value) should return the associated value",
        getValueForNullKey(),
        put(newEntry));

    Entry<K, V>[] expected = createArrayWithNullKey();

    int nullValueLocation = getNullLocation();
    Entry<K, V> oldEntry = array[nullValueLocation];
    array[nullValueLocation] = entry(oldEntry.getKey(), null);
    return array;
  }

  protected void initMapWithNullKey() {
    resetMap(createArrayWithNullKey());
  }

  protected void initMapWithNullValue() {
    resetMap(createArrayWithNullValue());
  }

  /**

    assertEqualIgnoringOrder(getSampleEntries(), entries);
  }

  @MapFeature.Require(ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)
  public void testForEach_nullKeys() {
    initMapWithNullKey();
    List<Entry<K, V>> expectedEntries = asList(createArrayWithNullKey());
    List<Entry<K, V>> entries = new ArrayList<>();
    getMap().forEach((k, v) -> entries.add(entry(k, v)));