@Override
        public @Nullable Object waitForValue() {
          return null;
        }

        @Override
        public void notifyNewValue(Object newValue) {}
      };

  /** Singleton placeholder that indicates a value is being loaded. */
  @SuppressWarnings("unchecked") // impl never uses a parameter or returns any non-null value
  static <K, V> ValueReference<K, V> unset() {

    public void test_fallbackAllRelevant_singleDoc() {
        List<String> docIds = Arrays.asList("singleDoc");
        RelevanceEvaluationResult result = RelevanceEvaluationResult.fallbackAllRelevant(docIds);

        assertTrue(result.isHasRelevantResults());
        assertEquals(1, result.getRelevantDocIds().size());
        assertEquals("singleDoc", result.getRelevantDocIds().get(0));
    }

    @Test

  public static <T> Ordering<T> explicit(T leastValue, T... remainingValuesInOrder) {
    return explicit(Lists.asList(leastValue, remainingValuesInOrder));
  }

  // Ordering<Object> singletons

  /**
   * Returns an ordering which treats all values as equal, indicating "no ordering." Passing this
   * ordering to any <i>stable</i> sort algorithm results in no change to the order of elements.

  public static <T> Ordering<T> explicit(T leastValue, T... remainingValuesInOrder) {
    return explicit(Lists.asList(leastValue, remainingValuesInOrder));
  }

  // Ordering<Object> singletons

  /**
   * Returns an ordering which treats all values as equal, indicating "no ordering." Passing this
   * ordering to any <i>stable</i> sort algorithm results in no change to the order of elements.

I suppose?'

  `Yes,' said Alice doubtfully:  `it means--to--make--anything--prettier.'

  `Well, then,' the Gryphon went on, `if you don't know what to
uglify is, you ARE a simpleton.'

  Alice did not feel encouraged to ask any more questions about
it, so she turned to the Mock Turtle, and said `What else had you
to learn?'

  `Well, there was Mystery,' the Mock Turtle replied, counting

I suppose?'

  `Yes,' said Alice doubtfully:  `it means--to--make--anything--prettier.'

  `Well, then,' the Gryphon went on, `if you don't know what to
uglify is, you ARE a simpleton.'

  Alice did not feel encouraged to ask any more questions about
it, so she turned to the Mock Turtle, and said `What else had you
to learn?'

  `Well, there was Mystery,' the Mock Turtle replied, counting