Add tests for batch duplicate guard in rec action invoke

Added InvokeBatchDuplicateGuardTests to verify that invoking batch rec actions with an existing BatchId throws BadRequestException, while using a new BatchId does not trigger the duplicate guard. Tests use MediatR ISender and real database data for integration coverage. Added necessary using directives.

tests/ReC.Tests/Application/RecActions/InvokeBatchDuplicateGuardTests.cs

@@ -0,0 +1,87 @@
+using System.Linq;
+using System.Threading.Tasks;
+using DigitalData.Core.Exceptions;
+using MediatR;
+using Microsoft.Extensions.DependencyInjection;
+using NUnit.Framework;
+using ReC.Application.RecActions.Commands;
+using ReC.Application.Results.Queries;
+
+namespace ReC.Tests.Application.RecActions;
+
+[TestFixture]
+public class InvokeBatchDuplicateGuardTests : RecApplicationTestBase
+{
+    private const long ProfileId = 3;
+
+    private (ISender Sender, IServiceScope Scope) CreateScopedSender()
+    {
+        var scope = ServiceProvider.CreateScope();
+        var sender = scope.ServiceProvider.GetRequiredService<ISender>();
+        return (sender, scope);
+    }
+
+    [Test]
+    public async Task Invoke_with_existing_batchId_throws_BadRequestException()
+    {
+        var (sender, scope) = CreateScopedSender();
+        using var _ = scope;
+
+        // Arrange: read an existing result to get a real BatchId from the database
+        var results = await sender.Send(new ReadResultViewQuery
+        {
+            ProfileId = ProfileId,
+            IncludeAction = false,
+            Last = true
+        });
+
+        var existingBatchId = results.FirstOrDefault()?.BatchId;
+        Assert.That(existingBatchId, Is.Not.Null.And.Not.Empty,
+            $"No results with a BatchId found for ProfileId {ProfileId}. Ensure test data exists in the database.");
+
+        // Act & Assert: invoking with the same BatchId should throw
+        var ex = Assert.ThrowsAsync<BadRequestException>(async () =>
+            await sender.Send(new InvokeBatchRecActionViewsCommand
+            {
+                ProfileId = ProfileId,
+                References = new InvokeReferences
+                {
+                    BatchId = existingBatchId!
+                }
+            }));
+
+        Assert.That(ex!.Message, Does.Contain(existingBatchId!));
+    }
+
+    [Test]
+    public void Invoke_with_new_batchId_does_not_throw_duplicate_guard()
+    {
+        var (sender, scope) = CreateScopedSender();
+        using var _ = scope;
+
+        var uniqueBatchId = $"test-{System.Guid.NewGuid():N}";
+
+        // This should NOT throw BadRequestException for duplicate BatchId.
+        // It may throw other exceptions (e.g., no actions found, endpoint errors),
+        // but the duplicate guard should pass.
+        try
+        {
+            sender.Send(new InvokeBatchRecActionViewsCommand
+            {
+                ProfileId = ProfileId,
+                References = new InvokeReferences
+                {
+                    BatchId = uniqueBatchId
+                }
+            }).GetAwaiter().GetResult();
+        }
+        catch (BadRequestException badReq) when (badReq.Message.Contains("already results associated"))
+        {
+            Assert.Fail("Duplicate guard should not trigger for a unique BatchId.");
+        }
+        catch
+        {
+            // Other exceptions (endpoint errors, etc.) are acceptable
+        }
+    }
+}