fix(site-event-logging): resolve SiteEventLogging-012..014 — fault dropped-event tasks, escape LIKE wildcards, re-triage startup-purge finding (Won't Fix)

tests/ScadaLink.SiteEventLogging.Tests/EventLogPurgeServiceTests.cs

@@ -225,6 +225,42 @@ public class EventLogPurgeServiceTests : IDisposable
         Assert.Equal(1L, newestPresent);
     }
 
+    [Fact]
+    public async Task StartAsync_DoesNotBlock_OnTheInitialPurge()
+    {
+        // SiteEventLogging-014 (re-triaged): on .NET 8+ BackgroundService runs
+        // ExecuteAsync on a thread-pool thread — the synchronous prelude (the
+        // initial RunPurge()) does NOT execute on the host startup thread, so
+        // StartAsync returns promptly and host startup / the /health/ready gate is
+        // not blocked even by a large initial purge. This test pins that behaviour:
+        // StartAsync returns fast, and the initial purge still happens shortly
+        // afterwards on the background scheduler.
+        InsertEventWithTimestamp(DateTimeOffset.UtcNow.AddDays(-31));
+        Assert.Equal(1, GetEventCount());
+
+        var purge = CreatePurgeService();
+        using var cts = new CancellationTokenSource();
+
+        var sw = System.Diagnostics.Stopwatch.StartNew();
+        await purge.StartAsync(cts.Token);
+        sw.Stop();
+
+        Assert.True(sw.ElapsedMilliseconds < 1000,
+            $"StartAsync blocked for {sw.ElapsedMilliseconds} ms — the initial purge " +
+            "must not run on the host startup thread.");
+
+        // The initial purge still runs on the background scheduler.
+        var deadline = DateTime.UtcNow.AddSeconds(5);
+        while (GetEventCount() != 0 && DateTime.UtcNow < deadline)
+        {
+            await Task.Delay(25);
+        }
+        Assert.Equal(0, GetEventCount());
+
+        await cts.CancelAsync();
+        await purge.StopAsync(CancellationToken.None);
+    }
+
     [Fact]
     public async Task PurgeByStorageCap_ConcurrentWritesDoNotCorruptConnection()
     {