fix DateConvert

hutool-core/src/test/java/cn/hutool/core/convert/ConvertToSBCAndDBCTest.java

@@ -3,8 +3,6 @@ package cn.hutool.core.convert;
 import org.junit.Assert;
 import org.junit.Test;
 
-import cn.hutool.core.convert.Convert;
-
 /**
  * 类型转换工具单元测试
  * 全角半角转换

hutool-core/src/test/java/cn/hutool/core/convert/DateConvertTest.java

@@ -21,6 +21,14 @@ public class DateConvertTest {
 		Assert.assertEquals(timeLong, value2.getTime());
 	}
 
+	@Test
+	public void toDateFromIntTest() {
+		int dateLong = -1497600000;
+		Date value = Convert.toDate(dateLong);
+		Assert.assertNotNull(value);
+		Assert.assertEquals("Mon Dec 15 00:00:00 CST 1969", value.toString());
+	}
+
 	@Test
 	public void toDateFromLocalDateTimeTest() {
 		LocalDateTime localDateTime = LocalDateTime.parse("2017-05-06T08:30:00", DateTimeFormatter.ISO_DATE_TIME);

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

@@ -2,6 +2,7 @@ package cn.hutool.core.date;
 
 import cn.hutool.core.collection.CollUtil;
 import cn.hutool.core.date.BetweenFormater.Level;
+import cn.hutool.core.lang.Console;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -624,6 +625,14 @@ public class DateUtilTest {
 		Assert.assertEquals("2017-05-06 08:30:00", date.toString());
 	}
 
+	@Test
+	public void dateTest2(){
+		// 测试负数日期
+		long dateLong = -1497600000;
+		final DateTime date = DateUtil.date(dateLong);
+		Assert.assertEquals("1969-12-15 00:00:00", date.toString());
+	}
+
 	@Test
 	public void ageTest(){
 		String d1 = "2000-02-29";