Improve resilience of tests

Those often fail in CI.

Author: acogoluegnes

src/test/java/com/rabbitmq/client/test/functional/ConnectionRecovery.java

@@ -160,10 +160,12 @@ public void shutdownCompleted(ShutdownSignalException cause) {
         });
         // note: we do not want to expose RecoveryCanBeginListener so this
         // test does not use it
+        final CountDownLatch recoveryCanBeginLatch = new CountDownLatch(1);
         ((AutorecoveringConnection)connection).getDelegate().addRecoveryCanBeginListener(new RecoveryCanBeginListener() {
             @Override
             public void recoveryCanBegin(ShutdownSignalException cause) {
                 events.add("recovery start hook 1");
+                recoveryCanBeginLatch.countDown();
             }
         });
         ((AutorecoveringConnection)connection).addRecoveryListener(new RecoveryListener() {
@@ -177,6 +179,7 @@ public void handleRecovery(Recoverable recoverable) {
         assertTrue(connection.isOpen());
         assertEquals("shutdown hook 1", events.get(0));
         assertEquals("shutdown hook 2", events.get(1));
+        recoveryCanBeginLatch.await(5, TimeUnit.SECONDS);
         assertEquals("recovery start hook 1", events.get(2));
         connection.close();
         wait(latch);

src/test/java/com/rabbitmq/client/test/functional/DeadLetterExchange.java

@@ -583,7 +583,7 @@ private void sleep(long millis) {
        publication time + TTL + latency */
     private void checkPromptArrival(QueueingConsumer c,
                                     int count, long latency) throws Exception {
-        long epsilon = TTL / 15;
+        long epsilon = TTL / 10;
         for (int i = 0; i < count; i++) {
             Delivery d = c.nextDelivery(TTL + TTL + latency + epsilon);
             assertNotNull("message #" + i + " did not expire", d);