fix: Make stopInstant be in sync with stopTimeNanos for split (#1610)

* fix: Make stopInstant in sync with stopTimeNanos

* Fix trailing whitespace

---------

Co-authored-by: Gary Gregory <garydgregory@users.noreply.github.com>

Author: larshelge

src/main/java/org/apache/commons/lang3/time/StopWatch.java

@@ -689,6 +689,7 @@ public void split() {
             throw new IllegalStateException("Stopwatch is not running.");
         }
         stopTimeNanos = System.nanoTime();
+        stopInstant = Instant.now();
         splitState = SplitState.SPLIT;
         splits.add(new Split(String.valueOf(splits.size()), Duration.ofNanos(stopTimeNanos - startTimeNanos)));
     }
@@ -710,6 +711,7 @@ public void split(final String label) {
             throw new IllegalStateException("Stopwatch is not running.");
         }
         stopTimeNanos = System.nanoTime();
+        stopInstant = Instant.now();
         splitState = SplitState.SPLIT;
         splits.add(new Split(label, Duration.ofNanos(stopTimeNanos - startTimeNanos)));
     }
@@ -835,5 +837,4 @@ public void unsplit() {
         splitState = SplitState.UNSPLIT;
         splits.remove(splits.size() - 1);
     }
-
 }

src/test/java/org/apache/commons/lang3/time/StopWatchTest.java

@@ -19,6 +19,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -422,6 +423,22 @@ void testSplitsWithStringLabels() {
         assertThrows(IllegalStateException.class, watch::unsplit);
     }
 
+    @Test
+    void testSplitGetStopInstant() {
+      final StopWatch watch = StopWatch.createStarted();
+      watch.split();
+      assertNotNull(watch.getStopTime());
+      assertNotNull(watch.getStopInstant());
+    }
+
+    @Test
+    void testSplitWithLabelGetStopInstant() {
+      final StopWatch watch = StopWatch.createStarted();
+      watch.split("one");
+      assertNotNull(watch.getStopTime());
+      assertNotNull(watch.getStopInstant());
+    }
+
     @Test
     void testStatic() {
         final StopWatch watch = StopWatch.createStarted();