--- jsr166/src/test/tck/ThreadLocalRandomTest.java	2017/09/19 20:10:49	1.25
+++ jsr166/src/test/tck/ThreadLocalRandomTest.java	2017/10/03 22:27:04	1.26
@@ -385,4 +385,24 @@ public class ThreadLocalRandomTest exten
         fail("all threads generate the same pseudo-random sequence");
     }
 
+    /**
+     * Repeated calls to nextBytes produce at least values of different signs for every byte
+     */
+    public void testNextBytes() {
+        ThreadLocalRandom rnd = ThreadLocalRandom.current();
+        int n = rnd.nextInt(20);
+        byte[] bytes = new byte[n];
+        outer:
+        for (int i = 0; i < n; i++) {
+            for (int tries = NCALLS; tries-->0; ) {
+                byte before = bytes[i];
+                rnd.nextBytes(bytes);
+                byte after = bytes[i];
+                if (after * before < 0)
+                    continue outer;
+            }
+            fail("not enough variation in random bytes");
+        }
+    }
+
 }