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));
  }

  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)

  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)

    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());
  }

  /**

  }

  @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();

  }

  @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());
  }

  /**