@Test
  public void testPutAll() {
    CustomEntryConcurrentHashMap empty = new CustomEntryConcurrentHashMap();
    CustomEntryConcurrentHashMap map = map5();
    empty.putAll(map);
    assertEquals(5, empty.size());
    assertTrue(empty.containsKey(one));
    assertTrue(empty.containsKey(two));
    assertTrue(empty.containsKey(three));
    assertTrue(empty.containsKey(four));
    assertTrue(empty.containsKey(five));
  }
putAll adds all key-value pairs from the given map
geode-core/src/integrationTest/java/org/apache/geode/internal/util/concurrent/cm/ConcurrentHashMapJUnitTest.java