diff --git a/tests/ScadaLink.SiteRuntime.Tests/Actors/InstanceActorIntegrationTests.cs b/tests/ScadaLink.SiteRuntime.Tests/Actors/InstanceActorIntegrationTests.cs
index 0bc84b1..68543f9 100644
--- a/tests/ScadaLink.SiteRuntime.Tests/Actors/InstanceActorIntegrationTests.cs
+++ b/tests/ScadaLink.SiteRuntime.Tests/Actors/InstanceActorIntegrationTests.cs
@@ -123,11 +123,9 @@ public class InstanceActorIntegrationTests : TestKit, IDisposable
                 $"corr-{i}", "Pump1", "Temperature", $"{i}", DateTimeOffset.UtcNow));
         }
 
-        // Wait for all to process
-        for (int i = 0; i < 50; i++)
-        {
-            ExpectMsg<SetStaticAttributeResponse>(TimeSpan.FromSeconds(10));
-        }
+        // SetStaticAttributeCommand is fire-and-forget; the GetAttributeRequest
+        // round-trip below is the sync point — the FIFO mailbox guarantees all
+        // 50 sets are processed before the get is.
 
         // The last value should be the final one
         actor.Tell(new GetAttributeRequest(
diff --git a/tests/ScadaLink.SiteRuntime.Tests/Actors/InstanceActorTests.cs b/tests/ScadaLink.SiteRuntime.Tests/Actors/InstanceActorTests.cs
index 20b5254..e205f5e 100644
--- a/tests/ScadaLink.SiteRuntime.Tests/Actors/InstanceActorTests.cs
+++ b/tests/ScadaLink.SiteRuntime.Tests/Actors/InstanceActorTests.cs
@@ -113,13 +113,12 @@ public class InstanceActorTests : TestKit, IDisposable
 
         var actor = CreateInstanceActor("Pump1", config);
 
-        // Set a static attribute -- response comes async via PipeTo
+        // SetStaticAttributeCommand is fire-and-forget (no reply); the
+        // GetAttributeRequest round-trip below confirms it was applied — the
+        // actor mailbox is FIFO, so the set is processed before the get.
         actor.Tell(new SetStaticAttributeCommand(
             "corr-3", "Pump1", "Temperature", "100.0", DateTimeOffset.UtcNow));
 
-        var setResponse = ExpectMsg<SetStaticAttributeResponse>(TimeSpan.FromSeconds(5));
-        Assert.True(setResponse.Success);
-
         // Verify the value changed in memory
         actor.Tell(new GetAttributeRequest(
             "corr-4", "Pump1", "Temperature", DateTimeOffset.UtcNow));
@@ -146,9 +145,12 @@ public class InstanceActorTests : TestKit, IDisposable
         actor.Tell(new SetStaticAttributeCommand(
             "corr-persist", "PumpPersist1", "Temperature", "100.0", DateTimeOffset.UtcNow));
 
-        ExpectMsg<SetStaticAttributeResponse>(TimeSpan.FromSeconds(5));
-
-        // Give async persistence time to complete
+        // SetStaticAttributeCommand is fire-and-forget; round-trip a
+        // GetAttributeRequest to confirm the command was processed (FIFO
+        // mailbox), then wait for the async SQLite persist to complete.
+        actor.Tell(new GetAttributeRequest(
+            "corr-persist-get", "PumpPersist1", "Temperature", DateTimeOffset.UtcNow));
+        ExpectMsg<GetAttributeResponse>(TimeSpan.FromSeconds(5));
         await Task.Delay(500);
 
         // Verify it persisted to SQLite