test code.

pulsar-broker/src/test/java/org/apache/pulsar/client/impl/NegativeAcksTest.java

@@ -19,6 +19,7 @@
 package org.apache.pulsar.client.impl;
 
 import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertNotNull;
 import static org.testng.Assert.assertNull;
 import static org.testng.Assert.assertTrue;
 import java.util.HashSet;
@@ -324,6 +325,11 @@ public void testNegativeAcksDeleteFromUnackedTracker() throws Exception {
         negativeAcksTracker.close();
     }
 
+    /**
+     * If we nack multiple messages in the same batch with different redelivery delays, the messages should be redelivered
+     * with the correct delay. However, all messages are redelivered at the same time.
+     * @throws Exception
+     */
     @Test
     public void testNegativeAcksWithBatch() throws Exception {
         cleanup();
@@ -356,17 +362,9 @@ public void testNegativeAcksWithBatch() throws Exception {
         Thread.sleep(2000);
         consumer.negativeAcknowledge(consumer.receive());
 
-        // wait for redelivery
-        Message<String> msg1 = consumer.receive();
-        long time1 = System.currentTimeMillis();
-        assertEquals(msg1.getValue(), "test-0");
-        Message<String> msg2 = consumer.receive();
-        long time2 = System.currentTimeMillis();
-        assertEquals(msg2.getValue(), "test-1");
-
-        // assert that the time duration between the two messages is greater than 1s,
-        // as the second nack is called 2s after the first nack
-        assertTrue(time2 - time1 >= 1000);
+        // now 2s has passed, the first message should be redelivered 1s later.
+        Message<String> msg1 = consumer.receive(2, TimeUnit.SECONDS);
+        assertNotNull(msg1);
     }
 
     @Test