datetime - Mocking time in Java 8's java.time API

Question

Joda Time has a nice DateTimeUtils.setCurrentMillisFixed() to mock time.

It's very practical in tests.

Is there an equivalent in Java 8's java.time API?

Answer 1

The closest thing is the Clock object. You can create a Clock object using any time you want (or from the System current time). All date.time objects have overloaded now methods that take a clock object instead for the current time. So you can use dependency injection to inject a Clock with a specific time:

public class MyBean {
    private Clock clock;  // dependency inject
    ...
    public void process(LocalDate eventDate) {
      if (eventDate.isBefore(LocalDate.now(clock)) {
        ...
      }
    }
  }

See Clock JavaDoc for more details