谁可以写一下这个工具类DateUtil的单元测试？求大神，要求单测报告不飘红，需要涵盖static方法、异常等

public class DateUtil {
public static Date parseDate(String dateStr, String pattern) {
SimpleDateFormat sdf = new SimpleDateFormat(pattern);
try {
return sdf.parse(dateStr);
} catch (ParseException e) {
// TODO Auto-generated catch block
return null;
}
}

     public static Date getBeforOneDay() {
        SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");
        Calendar c = Calendar.getInstance();
        try {
            c.add(Calendar.DATE, -1);
            return f.parse(f.format(c.getTime()));
        } catch (ParseException e) {
            e.printStackTrace();
            return null;
        }
    }

}

https://blog.csdn.net/zxl646801924/article/details/84105766

@Test
public void getBeforOneDayTest() {
    Date date = getBeforOneDay();
    System.out.println(date); //  Sun Apr 07 00:00:00 CST 2019
}
public static Date getBeforOneDay() {
    SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");
    Calendar c = Calendar.getInstance();
    try {
        c.add(Calendar.DATE, -1);
        return f.parse(f.format(c.getTime()));
    } catch (ParseException e) {
        e.printStackTrace();
        return null;
    }
}

import org.junit.Test;

import java.util.Date;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;

public class DateUtilTest {

@Test
public void parseDateTest() {
    int year = 2019;
    int month = 4;
    int date = 8;
    String pattern = "yyyy-MM-dd";

    // case 1: normal
    String dateStr = String.format("%d-%02d-%02d", year, month, date);
    Date result = DateUtil.parseDate(dateStr, pattern);
    Date expected = new Date(year - 1900, month - 1, date);

    assertEquals(expected, result);

    // case 2: wrong pattern
    dateStr = "something wrong";
    assertNull(DateUtil.parseDate(dateStr, pattern));
}

@Test
public void getBeforOneDayTest() {
    int year = 2019;
    int month = 4;
    int date = 8;
    String pattern = "yyyy-MM-dd";

    // case 1: normal
    assertEquals(new Date(year - 1900, month - 1, date), DateUtil.getBeforOneDay());
}

}

剩下的就是构造更多的用例去覆盖各种情况了。