function testComplement_OnlyOneValue() {
  var keyRange = lf.index.SingleKeyRange.only(20);
  var complementKeyRanges = keyRange.complement();
  assertEquals(2, complementKeyRanges.length);
  assertEquals('[unbound, 20)', complementKeyRanges[0].toString());
  assertEquals('(20, unbound]', complementKeyRanges[1].toString());
}
Tests KeyRange#complement() for the case where the original key range
includes a single value.