public void MemberJoinedActivityAdd()
{
const string guidStr = "515b7240-3be1-43d4-8846-c0b589cd1cd2";
var activityRepository = Substitute.For<IActivityRepository>();
IActivityService activityService = new ActivityService(activityRepository, _badgeRepository, _membershipRepository, _loggingService);
var user = new MembershipUser { Id = new Guid(guidStr), UserName = "******" };
activityService.MemberJoined(user);
activityRepository.Received().Add((Arg.Is<Activity>(x => x.Data == MemberJoinedActivity.KeyUserId + "=" + guidStr)));
}