--- a/graal/com.oracle.truffle.api.dsl.test/src/com/oracle/truffle/api/dsl/test/TestHelper.java	Tue Apr 14 15:12:48 2015 +0200
+++ b/graal/com.oracle.truffle.api.dsl.test/src/com/oracle/truffle/api/dsl/test/TestHelper.java	Tue Apr 14 15:12:48 2015 +0200
@@ -32,12 +32,27 @@
 import com.oracle.truffle.api.dsl.test.TypeSystemTest.ChildrenNode;
 import com.oracle.truffle.api.dsl.test.TypeSystemTest.TestRootNode;
 import com.oracle.truffle.api.dsl.test.TypeSystemTest.ValueNode;
+import com.oracle.truffle.api.frame.*;
+import com.oracle.truffle.api.nodes.*;
 
 /**
  * Utility class to provide some test helper functions.
  */
 class TestHelper {
 
+    // make nodes replacable
+    public static <T extends Node> T createRoot(final T node) {
+        new RootNode() {
+            @Child T child = node;
+
+            @Override
+            public Object execute(VirtualFrame frame) {
+                return null;
+            }
+        }.adoptChildren();
+        return node;
+    }
+
     private static ArgumentNode[] arguments(int count) {
         ArgumentNode[] nodes = new ArgumentNode[count];
         for (int i = 0; i < nodes.length; i++) {