Don't rely on test code execution time span for RemoteSegmentTransferTrackerTests (#15187)

Signed-off-by: Lukáš Vlček <[email protected]>

Author: lukas-vlcek

server/src/main/java/org/opensearch/index/remote/RemoteSegmentTransferTracker.java

@@ -65,7 +65,7 @@ public class RemoteSegmentTransferTracker extends RemoteTransferTracker {
     private volatile long remoteRefreshSeqNo;
 
     /**
-     * The refresh time of most recent remote refresh.
+     * The refresh time of the most recent remote refresh.
      */
     private volatile long remoteRefreshTimeMs;
 
@@ -76,7 +76,7 @@ public class RemoteSegmentTransferTracker extends RemoteTransferTracker {
     private volatile long remoteRefreshStartTimeMs = -1;
 
     /**
-     * The refresh time(clock) of most recent remote refresh.
+     * The refresh time(clock) of the most recent remote refresh.
      */
     private volatile long remoteRefreshClockTimeMs;
 

server/src/test/java/org/opensearch/index/remote/RemoteSegmentTransferTrackerTests.java

@@ -152,15 +152,18 @@ public void testComputeTimeLagOnUpdate() throws InterruptedException {
         transferTracker.updateLocalRefreshTimeMs(currentTimeMsUsingSystemNanos());
 
         transferTracker.updateLatestLocalFileNameLengthMap(List.of("test"), k -> 1L);
-        // Sleep for 100ms and then the lag should be within 100ms +/- 20ms
-        Thread.sleep(100);
-        assertTrue(Math.abs(transferTracker.getTimeMsLag() - 100) <= 20);
+        // Sleep for 100ms and then the lag should not be shorter
+        long span = 100;
+        Thread.sleep(span);
+        long lag = transferTracker.getTimeMsLag();
+        assertTrue("Actual lag [" + lag + "ms] is not expected to be shorter than span [" + span + "ms]", lag >= span);
 
         transferTracker.updateRemoteRefreshTimeMs(transferTracker.getLocalRefreshTimeMs());
         transferTracker.updateLocalRefreshTimeMs(currentTimeMsUsingSystemNanos());
-        long random = randomIntBetween(50, 200);
-        Thread.sleep(random);
-        assertTrue(Math.abs(transferTracker.getTimeMsLag() - random) <= 20);
+        long randomSpan = randomIntBetween(50, 200);
+        Thread.sleep(randomSpan);
+        lag = transferTracker.getTimeMsLag();
+        assertTrue("Actual lag [" + lag + "ms] is not expected to be shorter than span [" + randomSpan + "ms]", lag >= randomSpan);
     }
 
     public void testAddUploadBytesStarted() {