SocialPub/PrivaPub.Tests/Federation/ReplyRelayTests.cs

using MongoDB.Entities;

using PrivaPub.Domain.Statuses;
using PrivaPub.Models.Post;
using PrivaPub.Tests.Support;

using System.Text.Json.Nodes;

using static PrivaPub.Tests.Support.FederatedSeeds;

namespace PrivaPub.Tests.Federation
{
	// Inbox forwarding of replies (owner decision 2026-10-05): a reply to a persona's post reaches the persona's followers,
	// who are not among those its author's server sends it to
	[Trait("Category", "Integration")]
	public sealed class ReplyRelayTests : IAsyncLifetime
	{
		Harness _harness;

		public async ValueTask InitializeAsync()
		{
			Assert.SkipUnless(MongoFixture.Enabled, MongoFixture.Skip);
			_harness = await Harness.Start();
		}

		public async ValueTask DisposeAsync()
		{
			if (_harness != default)
				await _harness.DisposeAsync();
		}

		// alice's post; bob replies from his server, fan follows alice from another, pal from bob's
		async Task<(PrivaPub.Federation.Actors.LocalActor Alice, Post Post, RemoteActor Bob, RemoteActor Fan, RemoteActor Pal)> Thread()
		{
			var token = TestContext.Current.CancellationToken;
			var (_, alice) = await _harness.Persona("alice");
			var bob = new RemoteActor(_harness.Peer, "bob");
			var fan = new RemoteActor(_harness.Peer, "fan", _harness.Peer.B);
			var pal = new RemoteActor(_harness.Peer, "pal");
			await _harness.FollowedBy(alice, fan);
			await _harness.FollowedBy(alice, pal);
			var post = (await _harness.Statuses.Publish(alice, new StatusDraft { Text = "what do you think?" }, token)).Post;
			return (alice, post, bob, fan, pal);
		}

		JsonObject Reply(RemoteActor bob, Post post, string visibility = "public")
		{
			var reply = PublicNote(bob, "<p>I think so</p>", post.ActorURI);
			reply["inReplyTo"] = post.ObjectURI;
			if (visibility == "followers")
			{
				reply["to"] = new JsonArray(bob.Id + "/followers");
				reply["cc"] = new JsonArray(post.ActorURI);
			}
			return reply;
		}

		Task<List<JsonObject>> At(RemoteActor follower) => _harness.Outgoing(follower.SharedInbox);

		[Fact]
		public async Task A_public_reply_to_a_personas_post_reaches_its_followers_as_it_came_and_not_its_authors_server()
		{
			var (_, post, bob, fan, pal) = await Thread();
			var create = Create(bob, Reply(bob, post));
			create["signature"] = new JsonObject { ["type"] = "RsaSignature2017", ["signatureValue"] = "kept as it came" };

			await _harness.Deliver(bob, "/human-centipede", create);

			var relayed = Assert.Single(await At(fan), a => a["id"]!.GetValue<string>() == IdOf(create));
			Assert.Equal(bob.Id, relayed["actor"]!.GetValue<string>());
			Assert.Equal("kept as it came", relayed["signature"]!["signatureValue"]!.GetValue<string>());
			Assert.DoesNotContain(await At(pal), a => a["id"]!.GetValue<string>() == IdOf(create));
		}

		[Fact]
		public async Task Its_edit_and_deletion_follow_it_and_a_followers_only_reply_stays_where_it_was_sent()
		{
			var (_, post, bob, fan, _) = await Thread();
			var reply = Reply(bob, post);
			await _harness.Deliver(bob, "/human-centipede", Create(bob, reply));
			var edited = (JsonObject)reply.DeepClone();
			edited["content"] = "<p>I think so, on second thought</p>";
			edited["updated"] = DateTime.UtcNow.AddMinutes(1).ToString("O");
			var update = Activity(bob, "Update", edited);
			await _harness.Deliver(bob, "/human-centipede", update);
			var delete = Activity(bob, "Delete", JsonValue.Create(IdOf(reply))!);
			await _harness.Deliver(bob, "/human-centipede", delete);

			var relayed = (await At(fan)).Select(a => a["id"]!.GetValue<string>()).ToList();
			Assert.Contains(IdOf(update), relayed);
			Assert.Contains(IdOf(delete), relayed);

			var quiet = Create(bob, Reply(bob, post, "followers"));
			await _harness.Deliver(bob, "/human-centipede", quiet);
			Assert.DoesNotContain(await At(fan), a => a["id"]!.GetValue<string>() == IdOf(quiet));
		}

		[Fact]
		public async Task A_reply_that_reached_us_forwarded_is_not_passed_on_again()
		{
			var (_, post, bob, fan, _) = await Thread();
			var other = new RemoteActor(_harness.Peer, "other", _harness.Peer.B);
			var reply = Reply(bob, post);
			_harness.Peer.Serve(new Uri(IdOf(reply)).AbsolutePath, reply.ToJsonString());
			var create = Create(bob, reply);

			var result = await _harness.Deliver(other, "/human-centipede", create);

			Assert.Equal("forwarded", result.Reason);
			Assert.True(await DB.Default.Find<Post>().Match(p => p.ObjectURI == IdOf(reply)).ExecuteAnyAsync(TestContext.Current.CancellationToken));
			Assert.DoesNotContain(await At(fan), a => a["id"]!.GetValue<string>() == IdOf(create));
		}
	}
}