--- old/test/hotspot/jtreg/gc/ergonomics/TestDynamicNumberOfGCThreads.java	2018-11-28 19:19:27.796267612 +0100
+++ new/test/hotspot/jtreg/gc/ergonomics/TestDynamicNumberOfGCThreads.java	2018-11-28 19:19:27.638268719 +0100
@@ -29,10 +29,14 @@
  * @key gc
  * @modules java.base/jdk.internal.misc
  * @library /test/lib
+ * @build sun.hotspot.WhiteBox
+ * @run driver ClassFileInstaller sun.hotspot.WhiteBox sun.hotspot.WhiteBox$WhiteBoxPermission
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI TestDynamicNumberOfGCThreads
  */
 
 import jdk.test.lib.process.OutputAnalyzer;
 import jdk.test.lib.process.ProcessTools;
+import sun.hotspot.gc.GC;
 
 public class TestDynamicNumberOfGCThreads {
   public static void main(String[] args) throws Exception {
@@ -43,7 +47,9 @@
 
     testDynamicNumberOfGCThreads("UseParallelGC");
 
-    testDynamicNumberOfGCThreads("UseShenandoahGC");
+    if (GC.Shenandoah.isSupported()) {
+        testDynamicNumberOfGCThreads("UseShenandoahGC");
+    }
   }
 
   private static void verifyDynamicNumberOfGCThreads(OutputAnalyzer output) {