fix(scale): page mail and batch roles

JobTrackerApi.Tests/UsersControllerTests.cs

@@ -1,5 +1,6 @@
 using System.Security.Claims;
 using System.Linq.Expressions;
+using System.Data.Common;
 using JobTrackerApi.Controllers;
 using JobTrackerApi.Models;
 using JobTrackerApi.Services;
@@ -11,6 +12,10 @@ using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Options;
 using Microsoft.EntityFrameworkCore.Query;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Diagnostics;
+using Microsoft.Data.Sqlite;
+using JobTrackerApi.Data;
 using Moq;
 using Xunit;
 
@@ -102,6 +107,42 @@ public sealed class UsersControllerTests
         Assert.True(Assert.Single(rows, row => row.Id == member.Id).CanRemoveAdmin);
     }
 
+    [Fact]
+    public async Task List_uses_a_fixed_number_of_role_queries_for_many_users()
+    {
+        var counter = new CommandCounter();
+        await using var connection = new SqliteConnection("Data Source=:memory:");
+        await connection.OpenAsync();
+        var currentUser = new Mock<ICurrentUserService>();
+        currentUser.SetupGet(service => service.UserId).Returns("admin-1");
+        var options = new DbContextOptionsBuilder<JobTrackerContext>()
+            .UseSqlite(connection)
+            .AddInterceptors(counter)
+            .Options;
+        await using var db = new JobTrackerContext(options, currentUser.Object);
+        await db.Database.EnsureCreatedAsync();
+        var adminRole = new IdentityRole("Admin") { Id = "role-admin", NormalizedName = "ADMIN" };
+        var memberRole = new IdentityRole("Member") { Id = "role-member", NormalizedName = "MEMBER" };
+        db.Roles.AddRange(adminRole, memberRole);
+        var usersToAdd = Enumerable.Range(1, 75).Select(index => User(index == 1 ? "admin-1" : $"user-{index}")).ToList();
+        db.Users.AddRange(usersToAdd);
+        db.UserRoles.Add(new IdentityUserRole<string> { UserId = "admin-1", RoleId = adminRole.Id });
+        foreach (var user in usersToAdd.Skip(1))
+            db.UserRoles.Add(new IdentityUserRole<string> { UserId = user.Id, RoleId = memberRole.Id });
+        await db.SaveChangesAsync();
+        counter.Reset();
+
+        var manager = TestHostFactory.CreateUserManager();
+        var controller = CreateController(manager, "admin-1", db);
+        var action = await controller.List(CancellationToken.None);
+
+        var rows = Assert.IsType<List<UsersController.UserDto>>(Assert.IsType<OkObjectResult>(action.Result).Value);
+        Assert.Equal(75, rows.Count);
+        Assert.Equal(2, counter.ReaderCount);
+        manager.Verify(userManager => userManager.GetRolesAsync(It.IsAny<ApplicationUser>()), Times.Never);
+        manager.Verify(userManager => userManager.GetUsersInRoleAsync(It.IsAny<string>()), Times.Never);
+    }
+
     private static ApplicationUser User(string id) => new()
     {
         Id = id,
@@ -109,7 +150,7 @@ public sealed class UsersControllerTests
         UserName = $"{id}@example.com"
     };
 
-    private static UsersController CreateController(Mock<UserManager<ApplicationUser>> users, string currentUserId)
+    private static UsersController CreateController(Mock<UserManager<ApplicationUser>> users, string currentUserId, JobTrackerContext? db = null)
     {
         var roleStore = new Mock<IRoleStore<IdentityRole>>();
         var roles = new Mock<RoleManager<IdentityRole>>(
@@ -125,7 +166,8 @@ public sealed class UsersControllerTests
             Mock.Of<IAppEmailSender>(),
             new ConfigurationBuilder().Build(),
             new NullLogger<UsersController>(),
-            ExternalOrigin.Parse("http://localhost:3000", production: false));
+            ExternalOrigin.Parse("http://localhost:3000", production: false),
+            db: db);
 
         var identity = new ClaimsIdentity([new Claim(ClaimTypes.NameIdentifier, currentUserId)], "test");
         controller.ControllerContext = new ControllerContext
@@ -135,6 +177,23 @@ public sealed class UsersControllerTests
         return controller;
     }
 
+    private sealed class CommandCounter : DbCommandInterceptor
+    {
+        public int ReaderCount { get; private set; }
+
+        public void Reset() => ReaderCount = 0;
+
+        public override ValueTask<InterceptionResult<DbDataReader>> ReaderExecutingAsync(
+            DbCommand command,
+            CommandEventData eventData,
+            InterceptionResult<DbDataReader> result,
+            CancellationToken cancellationToken = default)
+        {
+            ReaderCount++;
+            return base.ReaderExecutingAsync(command, eventData, result, cancellationToken);
+        }
+    }
+
     private sealed class TestAsyncQueryProvider<TEntity>(IQueryProvider inner) : IAsyncQueryProvider
     {
         public IQueryable CreateQuery(Expression expression) => new TestAsyncEnumerable<TEntity>(expression);