merkle/compact: extra test coverage
merkle/compact: extra test coverage

RJPercival/trillian,AlCutter/trillian,daviddrysdale/trillian,gdbelvin/trillian,daviddrysdale/trillian,AlCutter/trillian,google/trillian,gdbelvin/trillian,Martin2112/trillian,Martin2112/trillian,gdbelvin/trillian,Martin2112/trillian,daviddrysdale/trillian,google/trillian,RJPercival/trillian