Index: core/src/test/scala/unit/kafka/log/LogManagerTest.scala
===================================================================
--- core/src/test/scala/unit/kafka/log/LogManagerTest.scala	(revision 1297324)
+++ core/src/test/scala/unit/kafka/log/LogManagerTest.scala	(working copy)
@@ -39,6 +39,7 @@
     config = new KafkaConfig(props) {
                    override val logFileSize = 1024
                    override val enableZookeeper = false
+                   override val flushInterval = 100
                  }
     logManager = new LogManager(config, null, time, -1, maxLogAge, false)
     logManager.startup
@@ -78,10 +79,13 @@
       offset += set.sizeInBytes
     }
     log.flush
-    // Why this sleep is required ? File system takes some time to update the last modified time for a file.
-    // TODO: What is unknown is why 1 second or couple 100 milliseconds didn't work ?
-    Thread.sleep(2000)
+
     assertTrue("There should be more than one segment now.", log.numberOfSegments > 1)
+
+    // update the last modified time of all log segments
+    val logSegments = log.segments.view
+    logSegments.foreach(s => s.file.setLastModified(time.currentMs))
+
     time.currentMs += maxLogAge + 3000
     logManager.cleanupLogs()
     assertEquals("Now there should only be only one segment.", 1, log.numberOfSegments)
@@ -109,6 +113,7 @@
       override val enableZookeeper = false
       override val logRetentionSize = (5 * 10 * setSize + 10).asInstanceOf[Long] // keep exactly 6 segments + 1 roll over
       override val logRetentionHours = retentionHours
+      override val flushInterval = 100
     }
     logManager = new LogManager(config, null, time, -1, retentionMs, false)
     logManager.startup
@@ -177,6 +182,7 @@
                    override val logFileSize = 256
                    override val enableZookeeper = false
                    override val topicPartitionsMap = Utils.getTopicPartitions("testPartition:2")
+                   override val flushInterval = 100
                  }
     
     logManager = new LogManager(config, null, time, -1, maxLogAge, false)