How can I mock JodaTime actual date?

Question

I want to test this method:

 public FirmOrder findActiveByModelColor(ModelColor modelColor) {
   Query query = em.createQuery("FROM FirmOrder fo WHERE fo.modelColor = :modelColor AND fo.year = :year AND fo.month = :month");
   query.setParameter("modelColor", modelColor);
   query.setParameter("year", new DateTime().year().get());
   query.setParameter("month", new DateTime().monthOfYear().get());
   return (FirmOrder) query.getSingleResult();
 }

but I need DateTime().year().get() and DateTime().dayOfMonth().get() to always return the same date

tks

score 59 · Accepted Answer · answered Dec 15 '10 at 19:51

59

If you can't add a factory object as suggested by skaffman, you can use DateTimeUtils.setCurrentMillisFixed().

answered Dec 15 '10 at 19:51

axtavt

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A comment so nice, I wanna like it twice. – Robert Fischer May 16 '12 at 00:19
6

Maybe you will want to reset it back to system with `setCurrentMillisSystem` after your test assertions. – Zero Distraction Mar 18 '14 at 06:19
7

This API modifies a global variable and therefore it must be avoided. – Aug 02 '14 at 15:59
@PolymorphicPotato Do you have an alternative suggestion? – EECOLOR Aug 10 '14 at 12:30
The way to do this properly in modern Java is to pass in a java.time.Clock instance and mock it in test. – Heuriskos Nov 11 '19 at 13:43

score 16 · Answer 2 · answered Dec 15 '10 at 19:46

16

Then you need to define a Clock interface, and inject it into your class

public interface Clock {
    DateTime getCurrentDateTime();
}

then:

Clock clock;

public FirmOrder findActiveByModelColor(ModelColor modelColor) {
   Query query = em.createQuery("FROM FirmOrder fo WHERE fo.modelColor = :modelColor AND fo.year = :year AND fo.month = :month");
   query.setParameter("modelColor", modelColor);
   query.setParameter("year", clock.getCurrentDateTime().year().get());
   query.setParameter("month", clock.getCurrentDateTime().dayOfMonth().get());
   return (FirmOrder) query.getSingleResult();
 }

Your test can then inject an implementation of Clock (e.g. using a mocking framework) that always returns a fixed time.

I use the Clock interface a lot in my own stuff, and I remain surprised that it's not part of one of the common libraries out there. I have two implementations I use a lot, WallClock and StoppedClock (which is useful for tests that use a fixed time).

answered Dec 15 '10 at 19:46

skaffman

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I like your idea. But I have couples question that I want to ask. `Clock#getCurrentDateTime()` will return me the current `JodaTime#DateTime`, which is great. However I need to compare the current DateTime to 4PM EST. In my code, I have this `fourPM = new DateTime(current.getYear(), current.getMonthOfYear(), current.getDayOfMonth(), 16, 0, 0, 0, DateTimeZone.forID("EST"));` for `current = new DateTime()` – Thang Pham May 18 '11 at 18:00
@Harry: You need to ask a new question – skaffman May 18 '11 at 18:04
I just create a new question. http://stackoverflow.com/questions/6049777/mockito-how-to-mock-an-interface-of-jodatime Please help – Thang Pham May 18 '11 at 19:05
How about `clock.now()` – Bart Swennenhuis Dec 07 '14 at 20:53
1

Joda Time provides the interface [MillisProvider](http://static.javadoc.io/joda-time/joda-time/2.9.7/org/joda/time/DateTimeUtils.MillisProvider.html) for this. Default implementation is [DateTimeUtils.SYSTEM_MILLIS_PROVIDER](http://static.javadoc.io/joda-time/joda-time/2.9.7/org/joda/time/DateTimeUtils.html#SYSTEM_MILLIS_PROVIDER) – Arend v. Reinersdorff Feb 03 '17 at 17:01
Your wish was fulfilled in Java 8: https://docs.oracle.com/javase/8/docs/api/java/time/Clock.html – Brad Mace Jan 29 '21 at 14:17

score 4 · Answer 3 · answered Feb 04 '11 at 14:02

Looks like the only option is to use the answer feature to post this comment:

The following portion of your code can lead to hard-to-detect errors:

query.setParameter("year", new DateTime().year().get());
query.setParameter("month", new DateTime().monthOfYear().get());

Let's pretend tha today is the last day of the year 2011 and this part of code is called 1 nano second prior to the new year and that the first statement takes more than 1 nano second to complete. This means that year will be set to 2011 but month to 1 but it had to best either to 2011/12 or 2012/1.

Though that statistically it is very unlikely to happen, but logically it can happen :)

You should create one DateTime instance and use that to populate both of year and month.

Okay, that's not really an answer to the OP, but I upvoted it because more people need to be aware of this problem. Given that many enterprise shops (and home set-ups) do compilation during the off-hours of the night (like 11:30 PM), this bug is actually surprisingly common — and annoying. It's usually more subtle, but it's why the StoppedClock mentioned in another answer is a good idea. — Robert Fischer, May 16 '12 at 00:18

score 1 · Answer 4 · edited Aug 17 '16 at 08:01

1

It's easy, if using the JMockit Expectations mocking API:

@Test
public void findActiveByModelColor()
{
    new NonStrictExpectations()
    {
        @Cascading DateTime dt;

        {
            dt.year().get(); result = 2010;
            dt.monthOfYear().get(); result = 12;
        }
    };

    FirmOrder fo = testedObject.findActiveByModelColor(modelColor);

    // asserts...
}

edited Aug 17 '16 at 08:01

Lukasz Stelmach

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answered Dec 16 '10 at 15:00

Rogério

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So, code that uses `DateTime` (or `java.util.Date`) like this is always bad? What about code using the Apache Commons Email API, which instantiates a `SimpleEmail` object and calls `send()` on it? Is it bad code? Why? – Rogério Dec 17 '10 at 18:41

How can I mock JodaTime actual date?

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