[Fact] public void CreatePost_ShouldCallAddOnRegistryGrain()
{
var postGrain = new Mock <IBlogPostRegistryGrain>();
var postId = Guid.NewGuid();
var post = new BlogPost {
};
_clusterClient.Setup(c => c.GetGrain <IBlogPostRegistryGrain>(0, null))
.Returns(() => postGrain.Object);
postGrain.Setup(g => g.Add(post)).Returns(() => Task.FromResult(postId));
_blogPostService.CreatePost(post).GetAwaiter().GetResult()
.Should().Be(postId, "because that's what the grain returns");
_clusterClient.Verify(c => c.GetGrain <IBlogPostRegistryGrain>(0, null), Times.Once,
"because we only need one instance of the grain");
postGrain.Verify(g => g.Add(post), Times.Once(), "because we only want to create it once");
}