--- jsr166/src/test/tck/Collection8Test.java	2016/11/28 15:31:40	1.33
+++ jsr166/src/test/tck/Collection8Test.java	2016/11/29 05:23:31	1.37
@@ -557,15 +557,20 @@ public class Collection8Test extends JSR
         if (!impl.isConcurrent()) return;
         final ThreadLocalRandom rnd = ThreadLocalRandom.current();
         final Collection c = impl.emptyCollection();
-        final long testDurationMillis = timeoutMillis();
+        final long testDurationMillis
+            = expensiveTests ? LONG_DELAY_MS : timeoutMillis();
         final AtomicBoolean done = new AtomicBoolean(false);
         final Object one = impl.makeElement(1);
         final Object two = impl.makeElement(2);
+        final Consumer checkSanity = x -> assertTrue(x == one || x == two);
+        final Consumer<Object[]> checkArraySanity = array -> {
+            // assertTrue(array.length <= 2); // duplicates are permitted
+            for (Object x : array) assertTrue(x == one || x == two);
+        };
         final Object[] emptyArray =
             (Object[]) java.lang.reflect.Array.newInstance(one.getClass(), 0);
         final List<Future<?>> futures;
         final Phaser threadsStarted = new Phaser(1); // register this thread
-        final Consumer checkSanity = x -> assertTrue(x == one || x == two);
         final Runnable[] frobbers = {
             () -> c.forEach(checkSanity),
             () -> c.stream().forEach(checkSanity),
@@ -581,8 +586,8 @@ public class Collection8Test extends JSR
                 do {} while (s.tryAdvance(checkSanity));
             },
             () -> { for (Object x : c) checkSanity.accept(x); },
-            () -> { for (Object x : c.toArray()) checkSanity.accept(x); },
-            () -> { for (Object x : c.toArray(emptyArray)) checkSanity.accept(x); },
+            () -> checkArraySanity.accept(c.toArray()),
+            () -> checkArraySanity.accept(c.toArray(emptyArray)),
             () -> {
                 assertTrue(c.add(one));
                 assertTrue(c.contains(one));