@Test
public void decryptionLocks_acquiresALunaUsageReadLock() throws Exception {

  when(keySet.get(activeKeyUuid))
    .thenReturn(firstActiveKey);
  subject.decrypt(new EncryptedValue(activeKeyUuid, "an encrypted value".getBytes(UTF_8), "a nonce".getBytes(UTF_8)));
  verify(readLock, times(1)).lock();
  verify(readLock, times(1)).unlock();
  verify(writeLock, times(0)).lock();
  verify(writeLock, times(0)).unlock();
}