### Question:
SCMSecurityProtocolServer implements SCMSecurityProtocol { public void start() { String startupMsg = StorageContainerManager.buildRpcServerStartMessage( "Starting RPC server for SCMSecurityProtocolServer.", getRpcAddress()); LOGGER.info(startupMsg); metrics.register(); getRpcServer().start(); } SCMSecurityProtocolServer(OzoneConfiguration conf,
      CertificateServer certificateServer); @Override String getDataNodeCertificate(
      DatanodeDetailsProto dnDetails,
      String certSignReq); @Override String getOMCertificate(OzoneManagerDetailsProto omDetails,
      String certSignReq); @Override String getCertificate(String certSerialId); @Override String getCACertificate(); RPC.Server getRpcServer(); InetSocketAddress getRpcAddress(); void start(); void stop(); void join();  }### Answer:
@Test public void testStart() { securityProtocolServer.start(); }