public IFixtureAsserter <TAggregate, TIdentity> When(params ICommand <TAggregate, TIdentity>[] commands)
        {
            if (commands == null)
            {
                throw new ArgumentNullException(nameof(commands));
            }

            if (!UsesAggregateManager && AggregateRef == ActorRefs.Nobody)
            {
                AggregateRef = _testKit.Sys.ActorOf(AggregateProps, AggregateId.Value);
            }

            foreach (var command in commands)
            {
                if (command == null)
                {
                    throw new NullReferenceException(nameof(command));
                }

                AggregateRef.Tell(command);
            }


            return(this);
        }
        public IFixtureExecutor <TAggregate, TIdentity> GivenNothing()
        {
            if (!UsesAggregateManager && AggregateRef.IsNobody())
            {
                AggregateRef = _testKit.Sys.ActorOf(AggregateProps, AggregateId.Value);
            }

            return(this);
        }