function testComplement_UpperBoundOnly() {
  var keyRange = lf.index.SingleKeyRange.upperBound(20);
  var complementKeyRanges = keyRange.complement();
  assertEquals(1, complementKeyRanges.length);
  assertEquals('(20, unbound]', complementKeyRanges[0].toString());

  keyRange = lf.index.SingleKeyRange.upperBound(20, true);
  complementKeyRanges = keyRange.complement();
  assertEquals(1, complementKeyRanges.length);
  assertEquals('[20, unbound]', complementKeyRanges[0].toString());
}
Tests KeyRange#complement() for the case where the original key range only
has an upper bound.