*/
    assertEquals(ImmutableSortedMap.of("a", 2.0, "b", 3.0), transformed);
  }

  @GwtIncompatible // NavigableMap
  public void testNavigableMapTransformValues() {
    NavigableMap<String, Integer> map = ImmutableSortedMap.of("a", 4, "b", 9);
    NavigableMap<String, Double> transformed = transformValues(map, SQRT_FUNCTION);