diff --git a/com.oracle.truffle.r.test/src/com/oracle/truffle/r/test/engine/interop/AbstractMRTest.java b/com.oracle.truffle.r.test/src/com/oracle/truffle/r/test/engine/interop/AbstractMRTest.java
index a92d2dfdbb3725ee7826f1d2b6e71accee2a04e9..45008be104c4d2adfb65bbbe0a174ed2fd1fb3f4 100644
--- a/com.oracle.truffle.r.test/src/com/oracle/truffle/r/test/engine/interop/AbstractMRTest.java
+++ b/com.oracle.truffle.r.test/src/com/oracle/truffle/r/test/engine/interop/AbstractMRTest.java
@@ -22,25 +22,24 @@
  */
 package com.oracle.truffle.r.test.engine.interop;
 
-import com.oracle.truffle.api.interop.ForeignAccess;
-import com.oracle.truffle.api.interop.InteropException;
-import com.oracle.truffle.api.interop.Message;
-import com.oracle.truffle.api.interop.TruffleObject;
-import com.oracle.truffle.api.interop.UnsupportedMessageException;
-import com.oracle.truffle.api.vm.PolyglotEngine;
-import com.oracle.truffle.r.ffi.impl.interop.NativePointer;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
 import java.util.HashSet;
 import java.util.Set;
 
 import org.junit.AfterClass;
 import org.junit.Assert;
 import org.junit.BeforeClass;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
 import org.junit.Test;
 
+import com.oracle.truffle.api.interop.ForeignAccess;
+import com.oracle.truffle.api.interop.InteropException;
+import com.oracle.truffle.api.interop.Message;
+import com.oracle.truffle.api.interop.TruffleObject;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
+import com.oracle.truffle.api.vm.PolyglotEngine;
+
 public abstract class AbstractMRTest {
 
     protected static PolyglotEngine engine;
@@ -117,7 +116,7 @@ public abstract class AbstractMRTest {
     @Test
     public void testIsPointer() throws Exception {
         for (TruffleObject obj : createTruffleObjects()) {
-            assertEquals(isPointer(obj), ForeignAccess.sendIsPointer(Message.IS_POINTER.createNode(), obj));
+            assertEquals(obj.getClass().getSimpleName(), isPointer(obj), ForeignAccess.sendIsPointer(Message.IS_POINTER.createNode(), obj));
         }
     }
 
@@ -125,7 +124,7 @@ public abstract class AbstractMRTest {
     public void testNativePointer() throws Exception {
         for (TruffleObject obj : createTruffleObjects()) {
             try {
-                assertTrue(ForeignAccess.sendToNative(Message.TO_NATIVE.createNode(), obj) instanceof NativePointer);
+                assertTrue(obj.getClass().getSimpleName(), ForeignAccess.sendToNative(Message.TO_NATIVE.createNode(), obj) == obj);
             } catch (UnsupportedMessageException unsupportedMessageException) {
             }
         }
diff --git a/com.oracle.truffle.r.test/src/com/oracle/truffle/r/test/engine/interop/ListMRTest.java b/com.oracle.truffle.r.test/src/com/oracle/truffle/r/test/engine/interop/ListMRTest.java
index d9c4aaa65ebeb5006ccd3d64187b81b4788ae5f8..2105850c641c044dc97d6b264dc5808f2aa54772 100644
--- a/com.oracle.truffle.r.test/src/com/oracle/truffle/r/test/engine/interop/ListMRTest.java
+++ b/com.oracle.truffle.r.test/src/com/oracle/truffle/r/test/engine/interop/ListMRTest.java
@@ -38,7 +38,6 @@ import com.oracle.truffle.api.interop.UnsupportedTypeException;
 import com.oracle.truffle.api.interop.java.JavaInterop;
 import com.oracle.truffle.api.source.Source;
 import com.oracle.truffle.api.vm.PolyglotEngine;
-import com.oracle.truffle.r.ffi.impl.interop.NativePointer;
 import com.oracle.truffle.r.runtime.data.RList;
 import com.oracle.truffle.r.runtime.data.RNull;
 import com.oracle.truffle.r.runtime.data.RPairList;
@@ -51,8 +50,9 @@ public class ListMRTest extends AbstractMRTest {
     @Override
     @Test
     public void testNativePointer() throws UnsupportedMessageException, UnknownIdentifierException, UnsupportedTypeException {
-        assertTrue(ForeignAccess.sendToNative(Message.TO_NATIVE.createNode(), create("list", testValues)) instanceof NativePointer);
-        assertTrue(ForeignAccess.sendToNative(Message.TO_NATIVE.createNode(), create("pairlist", testValues)) instanceof NativePointer);
+        for (TruffleObject obj : new TruffleObject[]{create("list", testValues), create("pairlist", testValues)}) {
+            assertTrue(ForeignAccess.sendToNative(Message.TO_NATIVE.createNode(), obj) == obj);
+        }
     }
 
     @Test