Merge pull request #357 from akarnokd/Fix309NegativeConstant

TCK: Request -1 in 309 instead of a random non-positive number

Author: viktorklang

Diff for: tck/src/main/java/org/reactivestreams/tck/PublisherVerification.java

@@ -885,7 +885,7 @@ public void required_spec309_requestNegativeNumberMustSignalIllegalArgumentExcep
       public void run(Publisher<T> pub) throws Throwable {
         final ManualSubscriber<T> sub = env.newManualSubscriber(pub);
         final Random r = new Random();
-        sub.request(-r.nextInt(Integer.MAX_VALUE));
+        sub.request(-r.nextInt(Integer.MAX_VALUE) - 1);
         sub.expectErrorWithMessage(IllegalArgumentException.class, "3.9"); // we do require implementations to mention the rule number at the very least
       }
     });