@Test
public void encryption_encryptionLocks_acquiresALunaUsageReadLock() throws Exception {

  reset(writeLock);
  when(keySet.getActive())
    .thenReturn(firstActiveKey);
  subject.encrypt("a value");
  verify(readLock, times(1)).lock();
  verify(readLock, times(1)).unlock();
  verify(writeLock, times(0)).unlock();
  verify(writeLock, times(0)).lock();
}