fix(store-and-forward): resolve StoreAndForward-006,007,008,009 — transactional parked reads, PipeTo, fault-isolated activity events; 002/011/012 deferred

tests/ScadaLink.StoreAndForward.Tests/StoreAndForwardServiceTests.cs

@@ -372,6 +372,50 @@ public class StoreAndForwardServiceTests : IAsyncLifetime, IDisposable
         Assert.Contains("Queued", activities);
     }
 
+    // ── StoreAndForward-009: faulting activity subscriber must not corrupt delivery ──
+
+    [Fact]
+    public async Task EnqueueAsync_ImmediateDeliverySuccess_FaultingActivitySubscriber_StillReportsDelivered()
+    {
+        // StoreAndForward-009: a throwing OnActivity subscriber (e.g. the site event
+        // log) must not be misclassified as a transient delivery failure. Pre-fix the
+        // subscriber's exception escaped RaiseActivity, was caught by EnqueueAsync's
+        // transient-failure handler, and a successfully delivered message was buffered.
+        _service.OnActivity += (_, _, _) => throw new InvalidOperationException("logging blew up");
+        _service.RegisterDeliveryHandler(StoreAndForwardCategory.ExternalSystem,
+            _ => Task.FromResult(true));
+
+        var result = await _service.EnqueueAsync(
+            StoreAndForwardCategory.ExternalSystem, "api", """{}""");
+
+        Assert.True(result.Accepted);
+        Assert.False(result.WasBuffered); // delivered, NOT buffered
+
+        var msg = await _storage.GetMessageByIdAsync(result.MessageId);
+        Assert.Null(msg); // nothing left in the buffer
+    }
+
+    [Fact]
+    public async Task RetryMessageAsync_FaultingActivitySubscriber_DoesNotIncrementRetryCount()
+    {
+        // StoreAndForward-009: a throwing subscriber raised after a successful retry
+        // delivery must not be caught by the retry-failure handler and counted as a
+        // transient failure.
+        var result = await _service.EnqueueAsync(
+            StoreAndForwardCategory.ExternalSystem, "api", """{}""",
+            attemptImmediateDelivery: false, maxRetries: 5);
+
+        _service.RegisterDeliveryHandler(StoreAndForwardCategory.ExternalSystem,
+            _ => Task.FromResult(true));
+        _service.OnActivity += (_, _, _) => throw new InvalidOperationException("logging blew up");
+
+        await _service.RetryPendingMessagesAsync();
+
+        // The retry succeeded; the message must be gone, not re-buffered with a bumped count.
+        var msg = await _storage.GetMessageByIdAsync(result.MessageId);
+        Assert.Null(msg);
+    }
+
     // ── WP-10: Per-source-entity retry settings ──
 
     [Fact]

tests/ScadaLink.StoreAndForward.Tests/StoreAndForwardStorageTests.cs

@@ -250,6 +250,39 @@ public class StoreAndForwardStorageTests : IAsyncLifetime, IDisposable
         Assert.Equal(2, page2.Count);
     }
 
+    [Fact]
+    public async Task GetParkedMessagesAsync_TransactionedReads_CountMatchesFullResultSet()
+    {
+        // StoreAndForward-006: the COUNT(*) and paged SELECT now run inside one
+        // transaction so they share a consistent snapshot. This functional check
+        // guards the fix — it verifies the transaction wiring did not break paging:
+        // the reported TotalCount and the rows assembled across all pages agree, and
+        // a page wide enough to hold every parked row contains exactly TotalCount rows.
+        for (int i = 0; i < 25; i++)
+        {
+            var m = CreateMessage($"txn-{i}", StoreAndForwardCategory.ExternalSystem);
+            m.Status = StoreAndForwardMessageStatus.Parked;
+            await _storage.EnqueueAsync(m);
+            await _storage.UpdateMessageAsync(m);
+        }
+
+        var (wholePage, wholeTotal) = await _storage.GetParkedMessagesAsync(pageNumber: 1, pageSize: 1000);
+        Assert.Equal(25, wholeTotal);
+        Assert.Equal(wholeTotal, wholePage.Count);
+
+        var collected = new List<string>();
+        int reportedTotal = -1;
+        for (int page = 1; ; page++)
+        {
+            var (rows, total) = await _storage.GetParkedMessagesAsync(pageNumber: page, pageSize: 7);
+            reportedTotal = total;
+            collected.AddRange(rows.Select(r => r.Id));
+            if (rows.Count < 7) break;
+        }
+        Assert.Equal(reportedTotal, collected.Count);
+        Assert.Equal(25, collected.Distinct().Count());
+    }
+
     [Fact]
     public async Task GetMessageCountByStatusAsync_ReturnsAccurateCount()
     {