helper.addValue(2);
    assertEquals(expected2, helper.toString());
  }

  @GwtIncompatible // Class names are obfuscated in GWT
  public void testToString_addValue() {
    String toTest =
        MoreObjects.toStringHelper(new TestClass())
            .add("field1", 1)
            .addValue("value1")
            .add("field2", "value2")
            .addValue(2)

    helper.addValue(2);
    assertEquals(expected2, helper.toString());
  }

  @GwtIncompatible // Class names are obfuscated in GWT
  public void testToString_addValue() {
    String toTest =
        MoreObjects.toStringHelper(new TestClass())
            .add("field1", 1)
            .addValue("value1")
            .add("field2", "value2")
            .addValue(2)

      s.add("valueStrength", Ascii.toLowerCase(valueStrength.toString()));
    }
    if (keyEquivalence != null) {
      s.addValue("keyEquivalence");
    }
    if (valueEquivalence != null) {
      s.addValue("valueEquivalence");
    }
    if (removalListener != null) {
      s.addValue("removalListener");
    }
    return s.toString();
  }

    }
  }

  @Override
  public String toString() {
    // TODO(dpb): Better toString, in the style of Futures.transform etc.
    return toStringHelper(this).add("state", state.get()).addValue(future).toString();
  }

  @SuppressWarnings("removal") // b/260137033
  @Override
  protected void finalize() {
    if (state.get().equals(OPEN)) {

      s.add("valueStrength", Ascii.toLowerCase(valueStrength.toString()));
    }
    if (keyEquivalence != null) {
      s.addValue("keyEquivalence");
    }
    if (valueEquivalence != null) {
      s.addValue("valueEquivalence");
    }
    if (removalListener != null) {
      s.addValue("removalListener");
    }
    return s.toString();
  }

  /**

        callback.onFailure(e);
        return;
      }
      callback.onSuccess(value);
    }

    @Override
    public String toString() {
      return MoreObjects.toStringHelper(this).addValue(callback).toString();
    }
  }

  /**
   * Returns the result of the input {@code Future}, which must have already completed.
   *