test: update ContextUtilsTest for millisecond ETag precision

Update the expected hash in testGetEtag to match the millisecond-precision
input, and add testGetEtagDistinguishesSubSecondChanges to lock in that
two timestamps one millisecond apart now produce different ETags.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: stian-sandvold

dhis-2/dhis-web-api/src/test/java/org/hisp/dhis/webapi/utils/ContextUtilsTest.java

@@ -31,6 +31,7 @@
 
 import static org.hisp.dhis.test.TestBase.getDate;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
 
 import java.util.Date;
 import org.hisp.dhis.user.User;
@@ -45,7 +46,20 @@ void testGetEtag() {
     user.setUid("kYt56BgfED2");
 
     assertEquals(
-        "7c9d6fd16b668638ca0e722aa2451054", ContextUtils.getEtag(date, UserDetails.fromUser(user)));
+        "ebcaa46bf9de4d04ea69cafcb3bd5caf", ContextUtils.getEtag(date, UserDetails.fromUser(user)));
+  }
+
+  @Test
+  void testGetEtagDistinguishesSubSecondChanges() {
+    User user = new User();
+    user.setUid("kYt56BgfED2");
+    UserDetails userDetails = UserDetails.fromUser(user);
+
+    Date date = getDate(2022, 03, 10);
+    Date oneMilliLater = new Date(date.getTime() + 1);
+
+    assertNotEquals(
+        ContextUtils.getEtag(date, userDetails), ContextUtils.getEtag(oneMilliLater, userDetails));
   }
 
   @Test