perf(search): keyset pagination (browse path) (#36)

2026-07-04 16:01:39 +02:00
parent 1e8feeef71
commit 3333e19452
11 changed files with 99 additions and 10 deletions
@@ -0,0 +1,57 @@
+using FluentAssertions;
+using InboxIntel.Application.Abstractions;
+using InboxIntel.Application.DTOs;
+using InboxIntel.Domain.Entities;
+using InboxIntel.Infrastructure.Persistence;
+using InboxIntel.Infrastructure.Search;
+using Microsoft.EntityFrameworkCore;
+using Xunit;
+
+namespace InboxIntel.IntegrationTests;
+
+/// <summary>
+/// RECOMMENDATIONS #8: keyset (cursor) pagination for the browse path — the window after a
+/// (SentAtUtc, Id) cursor returns the next rows with no duplicates/skips and no OFFSET scan.
+/// </summary>
+public class KeysetPaginationTests
+{
+    private sealed class FakeCurrentUser : ICurrentUser
+    {
+        public Guid UserId { get; set; }
+        public bool IsAuthenticated => UserId != Guid.Empty;
+    }
+
+    [Fact]
+    public async Task Cursor_window_continues_exactly_after_the_previous_page()
+    {
+        var user = Guid.NewGuid();
+        var opts = new DbContextOptionsBuilder<AppDbContext>()
+            .UseInMemoryDatabase(nameof(Cursor_window_continues_exactly_after_the_previous_page)).Options;
+
+        var baseline = DateTimeOffset.UtcNow;
+        using (var seed = new AppDbContext(opts, new FakeCurrentUser()))
+        {
+            var sender = new Sender { UserId = user, Address = "s@x.x" };
+            seed.Senders.Add(sender);
+            for (var i = 0; i < 5; i++)
+                seed.Emails.Add(new Email { UserId = user, GmailMessageId = $"m{i}", Sender = sender, SentAtUtc = baseline.AddMinutes(-i) });
+            await seed.SaveChangesAsync();
+        }
+
+        using var ctx = new AppDbContext(opts, new FakeCurrentUser { UserId = user });
+        var svc = new SearchService(ctx);
+
+        // First window via offset (page 1, size 2): m0, m1 (newest first).
+        var page1 = await svc.SearchAsync(user, new SearchRequestDto(null, null, null, null, null, null, null, false, 1, 2));
+        page1.Items.Select(i => i.GmailMessageId).Should().Equal("m0", "m1");
+
+        // Next window via cursor from the last row of page 1.
+        var last = page1.Items[^1];
+        var page2 = await svc.SearchAsync(user, new SearchRequestDto(
+            null, null, null, null, null, null, null, false, 1, 2,
+            AfterSentAtUtc: last.SentAtUtc, AfterId: last.Id));
+
+        page2.Items.Select(i => i.GmailMessageId).Should().Equal("m2", "m3"); // no dupes, no skips
+        page2.TotalCount.Should().Be(-1, "cursor windows skip the COUNT — that's the perf win");
+    }
+}