protected override void Given()
 {
     Sns.FindTopicAsync("TopicName")
     .Returns(new Topic {
         TopicArn = TopicArn
     });
     Sns.PublishAsync(Arg.Any <PublishRequest>())
     .Returns(PublishResult);
 }
 protected override Task WhenAsync()
 {
     Sns.PublishAsync(Arg.Any <PublishRequest>()).Returns(ThrowsException);
     return(Task.CompletedTask);
 }