SocialPub/PrivaPub.Tests/Infrastructure/PrivacyIdsTests.cs

using MongoDB.Bson;

using PrivaPub.Infrastructure.Ids;
using PrivaPub.Models.User;

using GroupEntity = PrivaPub.Models.Group.Group;

namespace PrivaPub.Tests.Infrastructure
{
	public class PrivacyIdsTests
	{
		[Fact]
		public void Persona_ids_carry_only_the_day_and_share_nothing_else()
		{
			var avatar = new Avatar();
			var first = (string)avatar.GenerateNewID();
			var second = (string)new Avatar { PublishedOn = avatar.PublishedOn }.GenerateNewID();
			var group = new GroupEntity();

			Assert.True(ObjectId.TryParse(first, out var a));
			Assert.True(ObjectId.TryParse(second, out var b));
			Assert.Equal(avatar.PublishedOn, a.CreationTime);
			Assert.InRange(a.CreationTime, DateTime.UtcNow.Date.AddDays(-13), DateTime.UtcNow.Date);
			Assert.Equal(a.CreationTime, b.CreationTime);
			Assert.NotEqual(first[8..14], second[8..14]);
			Assert.Equal(group.PublishedOn, ObjectId.Parse((string)group.GenerateNewID()).CreationTime);
		}

		[Fact]
		public void A_remote_post_id_sorts_by_its_published_time()
		{
			var older = PrivacyIds.At(new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc));
			var newer = PrivacyIds.At(new DateTime(2025, 1, 2, 0, 0, 0, DateTimeKind.Utc));

			Assert.True(string.CompareOrdinal(older, newer) < 0);
			Assert.Equal(new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc), ObjectId.Parse(older).CreationTime);
		}

		[Fact]
		public void A_post_arriving_live_sorts_after_everything_already_stored()
		{
			var local = ObjectId.GenerateNewId().ToString();
			var reply = PrivacyIds.Arrived(DateTime.UtcNow.AddSeconds(-30));
			var skewed = PrivacyIds.Arrived(DateTime.UtcNow.AddYears(50));

			Assert.True(string.CompareOrdinal(local, reply) < 0);
			Assert.True(string.CompareOrdinal(reply, skewed) < 0);
			Assert.True(ObjectId.Parse(skewed).CreationTime < DateTime.UtcNow.AddMinutes(1));
		}

		[Fact]
		public void A_backfilled_post_keeps_its_published_time() =>
			Assert.Equal(new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc), ObjectId.Parse(PrivacyIds.Arrived(new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc))).CreationTime);

		[Fact]
		public void A_persona_publishes_a_day_within_two_weeks_before_its_creation()
		{
			var created = new DateTime(2026, 10, 1, 15, 30, 0, DateTimeKind.Utc);
			var days = Enumerable.Range(0, 200).Select(_ => PrivacyIds.PublishedDay(created)).ToList();

			Assert.All(days, d => Assert.Equal(TimeSpan.Zero, d.TimeOfDay));
			Assert.All(days, d => Assert.InRange(d, created.Date.AddDays(-13), created.Date));
			Assert.True(days.Distinct().Count() > 1);
		}

		[Fact]
		public void A_published_time_in_the_future_is_clamped() =>
			Assert.True(ObjectId.Parse(PrivacyIds.At(DateTime.UtcNow.AddYears(50))).CreationTime < DateTime.UtcNow.AddDays(2));
	}
}