@Test
  public void testEnumeration() {
    CustomEntryConcurrentHashMap map = map5();
    Enumeration e = map.elements();
    int count = 0;
    while (e.hasMoreElements()) {
      count++;
      e.nextElement();
    }
    assertEquals(5, count);
  }
enumeration returns an enumeration containing the correct elements
geode-core/src/integrationTest/java/org/apache/geode/internal/util/concurrent/cm/ConcurrentHashMapJUnitTest.java