test(dcl): stabilize flaky DCL002 crash/restart subscription-preservation with condition-based wait (#234)

tests/ZB.MOM.WW.ScadaBridge.DataConnectionLayer.Tests/DataConnectionManagerActorTests.cs

@@ -76,7 +76,7 @@ public class DataConnectionManagerActorTests : TestKit
     }
 
     [Fact]
-    public async Task DCL002_ConnectionActorCrash_PreservesSubscriptionState()
+    public void DCL002_ConnectionActorCrash_PreservesSubscriptionState()
     {
         // Regression test for DataConnectionLayer-002. The supervisor used
         // Directive.Restart, which discards the connection actor's in-memory
@@ -103,7 +103,12 @@ public class DataConnectionManagerActorTests : TestKit
             new DataConnectionManagerActor(_mockFactory, _options, _mockHealthCollector)));
 
         manager.Tell(new CreateConnectionCommand("conn1", "OpcUa", new Dictionary<string, string>(), null, 3));
-        await Task.Delay(300); // connection actor reaches Connected
+        // Wait until the connection actor has called ConnectAsync (i.e. reached Connected)
+        // rather than sleeping a fixed 300 ms that can expire before the async connect
+        // completes under CPU contention.
+        AwaitCondition(
+            () => mockAdapter.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "ConnectAsync"),
+            TimeSpan.FromSeconds(5));
 
         // Register a subscription.
         manager.Tell(new SubscribeTagsRequest("c1", "inst1", "conn1", ["tag1"], DateTimeOffset.UtcNow));
@@ -111,7 +116,13 @@ public class DataConnectionManagerActorTests : TestKit
 
         // Crash the connection actor via a synchronously-throwing write.
         manager.Tell(new WriteTagRequest("c2", "conn1", "tag1", 42, DateTimeOffset.UtcNow));
-        await Task.Delay(300); // supervisor handles the failure
+        // Wait until WriteAsync was invoked, proving the WriteTagRequest was fully
+        // processed by the connection actor (and the supervisor's Resume directive
+        // applied) before we query health.  A fixed sleep can expire before the
+        // actor processes the message under CPU load.
+        AwaitCondition(
+            () => mockAdapter.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "WriteAsync"),
+            TimeSpan.FromSeconds(5));
 
         // After the crash the subscription state must survive: the health report
         // still shows the subscribed/resolved tag. With Restart it would be 0.