register_test_pass(tensorflow::OptimizationPassRegistry::PRE_PLACEMENT, 0,
                         std::make_unique<GraphErrorInjectionPass>(),
                         "error_injector");
  GraphErrorInjectionPass::enabled_ = true;

  tensorflow::ServerDef server_def = GetServerDef(3);
  // This server def has the task index set to 0.
  string serialized = server_def.SerializeAsString();