diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DiscoveryInjectionEndToEndTests.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DiscoveryInjectionEndToEndTests.cs
index 1a60b9a4..82a378ce 100644
--- a/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DiscoveryInjectionEndToEndTests.cs
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DiscoveryInjectionEndToEndTests.cs
@@ -74,6 +74,14 @@ public sealed class DiscoveryInjectionEndToEndTests : RuntimeActorTestBase
     private const string FixedTreeRef = "10.0.0.5:8193/Identity/SeriesNumber";
     private const string FixedTreeDisplayName = "SeriesNumber";
 
+    // The DETERMINISTIC NodeId the chain must place the FixedTree node at: EQ-1 (the bound equipment root) +
+    // the COLLAPSED folder path. The mapper's device-folder collapse drops the single shared device-host
+    // segment ("10.0.0.5:8193"), so FolderPathSegments ["FOCAS","10.0.0.5:8193","Identity"] + browse
+    // "SeriesNumber" → "EQ-1/FOCAS/Identity/SeriesNumber" (per EquipmentNodeIds.Variable). Asserting this
+    // EXACT NodeId closes the loop on the collapse rule — a prefix/StartsWith check would still pass if the
+    // collapse broke (e.g. "EQ-1/FOCAS/10.0.0.5:8193/Identity/SeriesNumber").
+    private const string ExpectedFixedTreeNodeId = "EQ-1/FOCAS/Identity/SeriesNumber";
+
     private static DiscoveredNode[] FixedTreeNodes() => new[]
     {
         new DiscoveredNode(
@@ -112,27 +120,25 @@ public sealed class DiscoveryInjectionEndToEndTests : RuntimeActorTestBase
         // Driver reports its captured FixedTree (the faithful Task-7/8 seam).
         host.Tell(new DriverInstanceActor.DiscoveredNodesReady("d1", FixedTreeNodes()));
 
-        // (a) The discovered variable was materialised through the REAL applier onto the sink, under EQ-1.
-        string fixedTreeNodeId = null!;
+        // (a) The discovered variable was materialised through the REAL applier onto the sink, at the EXACT
+        // collapsed NodeId under the bound equipment root (proves the mapper's device-folder collapse).
         AwaitAssert(() =>
         {
             var v = sink.Variables.SingleOrDefault(x => x.DisplayName == FixedTreeDisplayName);
-            v.NodeId.ShouldNotBeNull();          // EnsureVariable recorded for the FixedTree node
-            v.NodeId.ShouldStartWith("EQ-1");    // grafted UNDER the bound equipment root
-            v.DataType.ShouldBe("String");       // mapper carried the driver type through to the sink
-            v.Writable.ShouldBeFalse();          // discovered nodes are read-only
-            fixedTreeNodeId = v.NodeId;
-            sink.ModelChanges.ShouldContain("EQ-1"); // NodeAdded announced under the equipment
+            v.NodeId.ShouldBe(ExpectedFixedTreeNodeId); // EnsureVariable at the exact collapsed NodeId under EQ-1
+            v.DataType.ShouldBe("String");              // mapper carried the driver type through to the sink
+            v.Writable.ShouldBeFalse();                 // discovered nodes are read-only
+            sink.ModelChanges.ShouldContain("EQ-1");    // NodeAdded announced under the equipment
         }, duration: Timeout);
 
-        // (b) A value published for the FixedTree ref routes to the mapped NodeId and lands Good — the live
+        // (b) A value published for the FixedTree ref routes to THAT exact NodeId and lands Good — the live
         // value flowed end-to-end (host routing map → publish actor → applier-backing sink WriteValue).
         host.Tell(new DriverInstanceActor.AttributeValuePublished("d1", FixedTreeRef, "SN-12345", OpcUaQuality.Good, Ts));
 
         AwaitAssert(() =>
         {
-            var write = sink.Values.SingleOrDefault(x => x.NodeId == fixedTreeNodeId);
-            write.NodeId.ShouldBe(fixedTreeNodeId);
+            var write = sink.Values.SingleOrDefault(x => x.NodeId == ExpectedFixedTreeNodeId);
+            write.NodeId.ShouldBe(ExpectedFixedTreeNodeId);
             write.Value.ShouldBe("SN-12345");
             write.Quality.ShouldBe(OpcUaQuality.Good);
             write.Ts.ShouldBe(Ts);
@@ -159,22 +165,18 @@ public sealed class DiscoveryInjectionEndToEndTests : RuntimeActorTestBase
 
         host.Tell(new DriverInstanceActor.DiscoveredNodesReady("d1", FixedTreeNodes()));
 
-        // First injection: capture the mapped NodeId once it has materialised on the sink.
-        string fixedTreeNodeId = null!;
-        AwaitAssert(() =>
-        {
-            var v = sink.Variables.SingleOrDefault(x => x.DisplayName == FixedTreeDisplayName);
-            v.NodeId.ShouldNotBeNull();
-            fixedTreeNodeId = v.NodeId;
-        }, duration: Timeout);
+        // First injection: the FixedTree node materialises at the EXACT collapsed NodeId under EQ-1.
+        AwaitAssert(
+            () => sink.Variables.ShouldContain(x => x.NodeId == ExpectedFixedTreeNodeId && x.DisplayName == FixedTreeDisplayName),
+            duration: Timeout);
 
         // First value flows Good (pre-redeploy baseline).
         host.Tell(new DriverInstanceActor.AttributeValuePublished("d1", FixedTreeRef, "SN-AAA", OpcUaQuality.Good, Ts));
         AwaitAssert(
-            () => sink.Values.ShouldContain(x => x.NodeId == fixedTreeNodeId && Equals(x.Value, "SN-AAA") && x.Quality == OpcUaQuality.Good),
+            () => sink.Values.ShouldContain(x => x.NodeId == ExpectedFixedTreeNodeId && Equals(x.Value, "SN-AAA") && x.Quality == OpcUaQuality.Good),
             duration: Timeout);
 
-        var ensureVarCountBefore = sink.Variables.Count(x => x.NodeId == fixedTreeNodeId);
+        var ensureVarCountBefore = sink.Variables.Count(x => x.NodeId == ExpectedFixedTreeNodeId);
 
         // Apply a SECOND deployment (new revision, SAME d1 → EQ-1 binding) — re-runs PushDesiredSubscriptions
         // (clears + rebuilds the routing maps) then the Task-8 tail re-applies the cached discovered plan.
@@ -183,17 +185,17 @@ public sealed class DiscoveryInjectionEndToEndTests : RuntimeActorTestBase
         host.Tell(new DispatchDeployment(deploymentId2, RevB, CorrelationId.NewId()));
         coordinator.ExpectMsg<ApplyAck>(Timeout).Outcome.ShouldBe(ApplyAckOutcome.Applied);
 
-        // (a) The cached discovered plan was RE-MATERIALISED at the SAME NodeId after the redeploy rebuild.
+        // (a) The cached discovered plan was RE-MATERIALISED at the SAME exact NodeId after the redeploy rebuild.
         AwaitAssert(
-            () => sink.Variables.Count(x => x.NodeId == fixedTreeNodeId).ShouldBeGreaterThan(ensureVarCountBefore),
+            () => sink.Variables.Count(x => x.NodeId == ExpectedFixedTreeNodeId).ShouldBeGreaterThan(ensureVarCountBefore),
             duration: Timeout);
 
-        // (b) A value published AFTER the redeploy STILL routes to the mapped NodeId and lands Good — the
+        // (b) A value published AFTER the redeploy STILL routes to the exact NodeId and lands Good — the
         // live-value routing map was rebuilt by the re-apply (not lost when PushDesiredSubscriptions cleared it).
         var tsAfter = Ts.AddSeconds(5);
         host.Tell(new DriverInstanceActor.AttributeValuePublished("d1", FixedTreeRef, "SN-BBB", OpcUaQuality.Good, tsAfter));
         AwaitAssert(
-            () => sink.Values.ShouldContain(x => x.NodeId == fixedTreeNodeId && Equals(x.Value, "SN-BBB") && x.Quality == OpcUaQuality.Good),
+            () => sink.Values.ShouldContain(x => x.NodeId == ExpectedFixedTreeNodeId && Equals(x.Value, "SN-BBB") && x.Quality == OpcUaQuality.Good),
             duration: Timeout);
     }