public class SetHashCodeTester<E> extends AbstractSetTester<E> {
  public void testHashCode() {
    int expectedHashCode = 0;
    for (E element : getSampleElements()) {
      expectedHashCode += ((element == null) ? 0 : element.hashCode());
    }
    assertEquals(
        "A Set's hashCode() should be the sum of those of its elements.",
        expectedHashCode,
        getSet().hashCode());
  }

public class MapHashCodeTester<K, V> extends AbstractMapTester<K, V> {
  public void testHashCode() {
    int expectedHashCode = 0;
    for (Entry<K, V> entry : getSampleEntries()) {
      expectedHashCode += hash(entry);
    }
    assertEquals(
        "A Map's hashCode() should be the sum of those of its entries.",
        expectedHashCode,
        getMap().hashCode());
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)

public class SetHashCodeTester<E> extends AbstractSetTester<E> {
  public void testHashCode() {
    int expectedHashCode = 0;
    for (E element : getSampleElements()) {
      expectedHashCode += ((element == null) ? 0 : element.hashCode());
    }
    assertEquals(
        "A Set's hashCode() should be the sum of those of its elements.",
        expectedHashCode,
        getSet().hashCode());
  }

  public void testHashCode() {
    int expectedHashCode = 1;
    for (E element : getOrderedElements()) {
      expectedHashCode = 31 * expectedHashCode + ((element == null) ? 0 : element.hashCode());
    }
    assertEquals(
        "A List's hashCode() should be computed from those of its elements.",
        expectedHashCode,
        getList().hashCode());
  }

  /**

public class MapHashCodeTester<K, V> extends AbstractMapTester<K, V> {
  public void testHashCode() {
    int expectedHashCode = 0;
    for (Entry<K, V> entry : getSampleEntries()) {
      expectedHashCode += hash(entry);
    }
    assertEquals(
        "A Map's hashCode() should be the sum of those of its entries.",
        expectedHashCode,
        getMap().hashCode());
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)

  public void testHashCode() {
    int expectedHashCode = 1;
    for (E element : getOrderedElements()) {
      expectedHashCode = 31 * expectedHashCode + ((element == null) ? 0 : element.hashCode());
    }
    assertEquals(
        "A List's hashCode() should be computed from those of its elements.",
        expectedHashCode,
        getList().hashCode());
  }

  /**