Java spring assertEquals 语句中经过的瞬间时间

Question

I have some tests in my testsuite that run on all my colleagues, but fail on me. And that is to return two times from different entities in the form of an instant and compare them with each other. They actually match, but not for me.

This is the described line:

assertEquals(notUpdatedRule.getModStamp(), rule.getModStamp());

As error message I get back the following:

org.opentest4j.AssertionFailedError: 
Expected :2023-01-22T19:46:20.754829Z
Actual   :2023-01-22T19:46:20.754829486Z

I have already tried to adapt my openjdk version to that of my colleagues, but this has not changed anything.

Answer 1

I recommend that you use Instant.now(Clock clock) instead. From its JavaDocs : "Using this method allows the use of an alternate clock for testing."

The problems could arise from different time zones, different operating systems, different hardware precision of timers in your systems etc.

When you specify a Clock you could create that with a defined precision (milliseconds, seconds, minutes or any other Duration ) for your tests.

Or you could provide a Clock that always returns the same instant for your tests (which I really would recommend to have reproducible tests!) with Clock.fixed(Instant fixedInstant, ZoneId zone) .

For production use, you can simply provide a Clock.systemUTC() to have the current behaviour of Instant.now() . Clock s JavaDocs explain the reason for using it in more detail.