Assert isDone()

Author: henningandersen

server/src/main/java/org/elasticsearch/common/util/concurrent/EsExecutors.java

@@ -124,6 +124,7 @@ public static EsThreadPoolExecutor newAutoQueueFixed(String name, int size, int
      */
     public static Throwable rethrowErrors(Runnable runnable) {
         if (runnable instanceof RunnableFuture) {
+            assert ((RunnableFuture) runnable).isDone();
             try {
                 ((RunnableFuture) runnable).get();
             } catch (final Exception e) {