fix test

hutool-core/src/main/java/cn/hutool/core/date/CalendarUtil.java

@@ -396,13 +396,13 @@ public class CalendarUtil {
 	 * @return 年龄
 	 */
 	protected static int age(long birthday, long dateToCompare) {
-		Calendar cal = Calendar.getInstance();
-		cal.setTimeInMillis(dateToCompare);
-
-		if (cal.before(birthday)) {
+		if (birthday > dateToCompare) {
 			throw new IllegalArgumentException("Birthday is after dateToCompare!");
 		}
 
+		final Calendar cal = Calendar.getInstance();
+		cal.setTimeInMillis(dateToCompare);
+
 		final int year = cal.get(Calendar.YEAR);
 		final int month = cal.get(Calendar.MONTH);
 		final int dayOfMonth = cal.get(Calendar.DAY_OF_MONTH);

hutool-core/src/test/java/cn/hutool/core/date/DateUtilTest.java

@@ -700,8 +700,7 @@ public class DateUtilTest {
 	public void ageTest2(){
 		String d1 = "2019-02-29";
 		String d2 = "2018-02-28";
-		final int age = DateUtil.age(DateUtil.parseDate(d1), DateUtil.parseDate(d2));
-		Assert.assertEquals(18, age);
+		DateUtil.age(DateUtil.parseDate(d1), DateUtil.parseDate(d2));
 	}
 
 	@Test