import org.junit.Test;

import java.time.Instant;

import java.time.LocalDate;

import java.time.LocalDateTime;

import java.time.ZoneId;

import java.util.Calendar;

import java.util.Date;

import java.util.GregorianCalendar;

import static org.junit.Assert.assertEquals;

public class Java8DateTimeTest {

@Test

public void testConvertLocalDateToDate() {

LocalDate localDate = LocalDate.of(2017, 8, 10);

Date date = Date.from(localDate.atStartOfDay().atZone(ZoneId.systemDefault()).toInstant());

Calendar calendar = Calendar.getInstance();

calendar.setTime(date);

assertEquals(localDate.getYear(), calendar.get(Calendar.YEAR));

assertEquals(localDate.getMonth().getValue(), calendar.get(Calendar.MONTH) + 1);

assertEquals(localDate.getDayOfMonth(), calendar.get(Calendar.DAY_OF_MONTH));

}

@Test

public void testConvertLocalDateTimeToDate() {

LocalDateTime localDateTime = LocalDateTime.of(2017, 8, 10, 23, 10, 15);

Date date = Date.from(localDateTime.atZone(ZoneId.systemDefault()).toInstant());

Calendar calendar = Calendar.getInstance();

calendar.setTime(date);

assertEquals(localDateTime.getYear(), calendar.get(Calendar.YEAR));

assertEquals(localDateTime.getMonth().getValue(), calendar.get(Calendar.MONTH) + 1);

assertEquals(localDateTime.getDayOfMonth(), calendar.get(Calendar.DAY_OF_MONTH));

}

@Test

public void testConvertDateToLocalDate() {

Calendar calendar = new GregorianCalendar(2017, Calendar.AUGUST, 20);

Date date = calendar.getTime();

//Convert Date to LocalDate

LocalDate localDate = Instant.ofEpochMilli(date.getTime()).atZone(

ZoneId.systemDefault()).toLocalDate();

assertEquals(calendar.get(Calendar.YEAR), localDate.getYear());

assertEquals(calendar.get(Calendar.MONTH) + 1, localDate.getMonth()

.getValue());

assertEquals(calendar.get(Calendar.DAY_OF_MONTH), localDate.getDayOfMonth());

}

@Test

public void testConvertDateToLocalDateTime() {

Calendar calendar = new GregorianCalendar(2017, Calendar.AUGUST, 20);

Date date = calendar.getTime();

//Convert Date to LocalDateTime

LocalDateTime localDateTime = Instant.ofEpochMilli(date.getTime()).atZone(ZoneId

.systemDefault()).toLocalDateTime();

assertEquals(calendar.get(Calendar.YEAR), localDateTime.getYear());

assertEquals(calendar.get(Calendar.MONTH) + 1, localDateTime.getMonth()

.getValue());

assertEquals(calendar.get(Calendar.DAY_OF_MONTH), localDateTime.getDayOfMonth());

assertEquals(calendar.get(Calendar.HOUR_OF_DAY), localDateTime.getHour());

assertEquals(calendar.get(Calendar.MINUTE), localDateTime.getMinute());

assertEquals(calendar.get(Calendar.SECOND), localDateTime.getSecond());

}

}