--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/truffle/com.oracle.truffle.sl.test/src/com/oracle/truffle/sl/test/instrument/InstrumentationTestMode.java	Wed Sep 30 16:34:53 2015 -0700
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2014, 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * The Universal Permissive License (UPL), Version 1.0
+ *
+ * Subject to the condition set forth below, permission is hereby granted to any
+ * person obtaining a copy of this software, associated documentation and/or
+ * data (collectively the "Software"), free of charge and under any and all
+ * copyright rights in the Software, and any and all patent rights owned or
+ * freely licensable by each licensor hereunder covering either (i) the
+ * unmodified Software as contributed to or provided by such licensor, or (ii)
+ * the Larger Works (as defined below), to deal in both
+ *
+ * (a) the Software, and
+ *
+ * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
+ * one is included with the Software each a "Larger Work" to which the Software
+ * is contributed by such licensors),
+ *
+ * without restriction, including without limitation the rights to copy, create
+ * derivative works of, display, perform, and distribute the Software and make,
+ * use, sell, offer for sale, import, export, have made, and have sold the
+ * Software and the Larger Work(s), and to sublicense the foregoing rights on
+ * either these or other terms.
+ *
+ * This license is subject to the following condition:
+ *
+ * The above copyright notice and either this complete permission notice or at a
+ * minimum a reference to the UPL must be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.oracle.truffle.sl.test.instrument;
+
+import static org.junit.Assert.fail;
+
+import java.lang.reflect.Field;
+
+import com.oracle.truffle.api.instrument.Instrumenter;
+import com.oracle.truffle.api.vm.PolyglotEngine;
+
+public class InstrumentationTestMode {
+
+    public static void set(boolean enable) {
+
+        try {
+            final PolyglotEngine vm = PolyglotEngine.buildNew().build();
+            final Field instrumenterField = vm.getClass().getDeclaredField("instrumenter");
+            instrumenterField.setAccessible(true);
+            final Object instrumenter = instrumenterField.get(vm);
+            final java.lang.reflect.Field testVMField = Instrumenter.class.getDeclaredField("testVM");
+            testVMField.setAccessible(true);
+            if (enable) {
+                testVMField.set(instrumenter, vm);
+            } else {
+                testVMField.set(instrumenter, null);
+            }
+        } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException ex) {
+            fail("Reflective access to Instrumenter for testing");
+        }
+
+    }
+}