Make unit tests with dates pass in all time zones and with/out DST

Question

How do I make this unit test pass in all time zones independent of whether DST is active or not?

import static org.junit.Assert.*;
import java.text.SimpleDat         


        

Answer 1

By default, a new SimpleDateFormat will use the system default time zone. If you want a specific time zone, you should call setTimeZone on it:

private final static SimpleDateFormat DATE_FORMAT = createFormat();

private static SimpleDateFormat createFormat() {
    // Make sure there are no locale-specific nasties, either...
    SimpleDateFormat ret = new SimpleDateFormat("yyyy.MM.dd'T'HH:mm.ss:SSSZZ",
                                                Locale.US);
    ret.setTimeZone(TimeZone.getTimeZone("Etc/UTC");
}

For your second test, you'd want to change it to:

new DateTime(0L, DateTimeZone.UTC);

Note that you shouldn't usually use a static SimpleDateFormat variable, as it's not thread-safe. (Whereas the Joda Time DateTimeFormatter implementation is thread-safe.)