This post outlined a possible way to test time-dependent logic by abstracting the concept of current time behind a clock interface and providing a mock clock implementation for the tests. This is important because otherwise relying on the system clock to test, say, if a particular action is triggered every day at 12.00 might be tricky.
JodaTime makes it easier to implement the above. It already provides a MillisProvider interface (to abstract the concept of current time) which can be accessed through methods from the DateTimeUtils class, thus saving you from writing your own.
//fix the current time to 1000 millis DateTimeUtils.setCurrentMillisFixed(1000); ... run time-dependent logic //time is still at 1000 millis long time = DateTimeUtils.getCurrentMillis();