MessageUtils { @VisibleForTesting ModSeq nextModSeq(Mailbox mailbox) throws MailboxException { return modSeqProvider.nextModSeq(mailbox); } MessageUtils(UidProvider uidProvider, ModSeqProvider modSeqProvider);   }
@Test void nextModSeqShouldCallModSeqProvider() throws Exception { messageUtils.nextModSeq(mailbox); verify(modSeqProvider).nextModSeq(eq(mailbox)); }