case 0:
                    return emptyMap();
                case 1:
                    Map.Entry<K, V> entry = map.entrySet().iterator().next();
                    return singletonMap(entry.getKey(), entry.getValue());
                default:
                    return new MapN<>(map);
            }
        }
    }

    @SuppressWarnings("unchecked")
    static <K, V> Map<K, V> emptyMap() {

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)
  public void testRemove_present() {
    getSet().remove(e0());
    assertFalse(
        "After remove(present) a set should not contain the removed element.",
        getSet().contains(e0()));
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)
  public void testRemove_present() {
    getSet().remove(e0());
    assertFalse(
        "After remove(present) a set should not contain the removed element.",
        getSet().contains(e0()));
  }

        }

        MetadataGraphNode node = new MetadataGraphNode(md);
        addNode(node);
        return node;
    }

    /**
     * getter
     */
    public MetadataGraphNode getEntry() {
        return entry;
    }

    /**
     * getter
     */
    public Collection<MetadataGraphNode> getNodes() {
        return nodes;
    }

        valueMap.put("user", user.map(FessUserBean::getUserId).orElse("-"));
        final Comparator<Map.Entry<String, String>> c = Comparator.comparing(Map.Entry::getKey);
        params.entrySet().stream().sorted(c).forEach(e -> {
            valueMap.put(e.getKey(), e.getValue().replace('\t', '_'));
        });
        log(valueMap);
    }

    /**
     * Log the value map.
     * @param valueMap The value map.

    Iterator<Entry<K, V>> iterator = multimap().entries().iterator();
    Entry<K, V> entry = iterator.next();
    K key = entry.getKey();
    V value = entry.getValue();
    multimap().removeAll(key);
    assertEquals(key, entry.getKey());
    assertEquals(value, entry.getValue());
  }

      expectedHashCode += (element == null) ? 0 : element.hashCode();
    }
    assertEquals(
        "A Set's hashCode() should be the sum of those of its elements.",
        expectedHashCode,
        getSet().hashCode());
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  public void testHashCode_containingNull() {

      ImmutableList.Builder<V> valuesBuilder = new ImmutableList.Builder<>(entries.size());
      for (int i = 0; i < entries.size(); i++) {
        Range<K> range = entries.get(i).getKey();
        if (i > 0) {
          Range<K> prevRange = entries.get(i - 1).getKey();
          if (range.isConnected(prevRange) && !range.intersection(prevRange).isEmpty()) {
            throw new IllegalArgumentException(

    Entry<String, Integer> entry = entries.next();
    assertEquals("bar", entry.getKey());
    assertEquals(1, (int) entry.getValue());
    entry = entries.next();
    assertEquals("foo", entry.getKey());
    assertEquals(2, (int) entry.getValue());
    entry.setValue(4);
    entry = entries.next();
    assertEquals("bar", entry.getKey());
    assertEquals(3, (int) entry.getValue());
    assertFalse(entries.hasNext());

        // These tests verify the PingResponse class structure is correct
        assertTrue(true);
    }

    public void test_getClusterName_returnsCorrectValue() {
        // Test cluster name getter exists
        FessConfig mockConfig = new FessConfig.SimpleImpl() {
            private static final long serialVersionUID = 1L;

            @Override
            public Set<String> getApiPingEsFieldSet() {