perf(adminui): pooled DbContext factory; role-grants reads per-call, not per-circuit

tests/Core/ZB.MOM.WW.OtOpcUa.Configuration.Tests/LdapGroupRoleMappingServiceTests.cs

@@ -1,4 +1,5 @@
 using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Storage;
 using Shouldly;
 using Xunit;
 using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
@@ -8,21 +9,9 @@ using ZB.MOM.WW.OtOpcUa.Configuration.Services;
 namespace ZB.MOM.WW.OtOpcUa.Configuration.Tests;
 
 [Trait("Category", "Unit")]
-public sealed class LdapGroupRoleMappingServiceTests : IDisposable
+public sealed class LdapGroupRoleMappingServiceTests
 {
-    private readonly OtOpcUaConfigDbContext _db;
-
-    /// <summary>Initializes a new instance of the LdapGroupRoleMappingServiceTests class.</summary>
-    public LdapGroupRoleMappingServiceTests()
-    {
-        var options = new DbContextOptionsBuilder<OtOpcUaConfigDbContext>()
-            .UseInMemoryDatabase($"ldap-grm-{Guid.NewGuid():N}")
-            .Options;
-        _db = new OtOpcUaConfigDbContext(options);
-    }
-
-    /// <summary>Disposes the database context.</summary>
-    public void Dispose() => _db.Dispose();
+    private readonly RecordingContextFactory _db = new();
 
     private LdapGroupRoleMapping Make(string group, AdminRole role, string? clusterId = null, bool? isSystemWide = null) =>
         new()
@@ -165,4 +154,48 @@ public sealed class LdapGroupRoleMappingServiceTests : IDisposable
         var byGroup = await svc.GetByGroupsAsync(["cn=sysadmins,dc=x"], CancellationToken.None);
         byGroup.ShouldContain(r => r.Id == saved.Id);
     }
+
+    /// <summary>
+    ///     The service must take its context from the factory PER CALL and dispose it before returning —
+    ///     it must never pin one context (and therefore one pooled connection) for its own lifetime. That
+    ///     is what makes it safe on the RoleGrants Blazor page, where the DI scope is the circuit and two
+    ///     renders can overlap: a pinned context would throw
+    ///     "A second operation was started on this context instance" the first time they did.
+    /// </summary>
+    [Fact]
+    public async Task Every_call_creates_and_disposes_its_own_context()
+    {
+        var svc = new LdapGroupRoleMappingService(_db);
+
+        await svc.CreateAsync(Make("cn=fleet,dc=x", AdminRole.Administrator), CancellationToken.None);
+        await svc.ListAllAsync(CancellationToken.None);
+        await svc.GetByGroupsAsync(["cn=fleet,dc=x"], CancellationToken.None);
+
+        // One context per call, and no leftovers: a service holding its own context would show 0.
+        _db.Created.Count.ShouldBe(3);
+        foreach (var ctx in _db.Created)
+            Should.Throw<ObjectDisposedException>(() => ctx.LdapGroupRoleMappings.ToList());
+    }
+
+    /// <summary>
+    ///     Hands out a fresh <see cref="OtOpcUaConfigDbContext"/> per call over one shared in-memory store
+    ///     (an explicit <see cref="InMemoryDatabaseRoot"/>, so every context genuinely sees the same rows),
+    ///     and records what it created so a test can assert the per-call create/dispose discipline.
+    /// </summary>
+    private sealed class RecordingContextFactory : IDbContextFactory<OtOpcUaConfigDbContext>
+    {
+        private readonly DbContextOptions<OtOpcUaConfigDbContext> _options =
+            new DbContextOptionsBuilder<OtOpcUaConfigDbContext>()
+                .UseInMemoryDatabase($"ldap-grm-{Guid.NewGuid():N}", new InMemoryDatabaseRoot())
+                .Options;
+
+        public List<OtOpcUaConfigDbContext> Created { get; } = [];
+
+        public OtOpcUaConfigDbContext CreateDbContext()
+        {
+            var ctx = new OtOpcUaConfigDbContext(_options);
+            Created.Add(ctx);
+            return ctx;
+        }
+    }
 }