Groovy: Date and Time comparisons with a slight delay - datetime

Question

So I have the following script:
import groovy.time.TimeCategory
def dueDate = context.expand( '${Test 4 - create user task#Response#$[\'_embedded\'][\'userTaskDtoList\'][0][\'dueDate\']}' )
def date = new Date(messageExchange.getTimestamp())
use(groovy.time.TimeCategory){
after24Hours = (date + 24.hours).format("yyyy-MM-dd'T'HH:mm:ss'Z'", TimeZone.getTimeZone('UTC')) }
assert dueDate == after24Hours
What I'm trying to do with this is take the date and time from a REST request (dueDate - which comes in UTC format and with a 24h delay) and create a new date and time from the timestamp of the moment when that request has been sent, which is registered from my system. I then convert that time to UTC to accommodate the format from dueDate and add 24h to it. At the end I verify that the date and time from dueDate and after24Hours is the same.
The output does return the same time but in certain cases if there is a delay between the time the request is being sent and the time is received then the assertion will fail. This depends on the server, usually there is a difference of like 1 millisecond but I'm thinking that if the server will be slower at some point this will definitely be bigger.
What could I do to allow some margin of error in the assertion, maybe like a few seconds or even a couple of minutes?
Ok, so I managed to do this:
import groovy.time.*
def dueDate = context.expand( '${Test 4 - create user task#Response#$[\'_embedded\'][\'userTaskDtoList\'][0][\'dueDate\']}' )
def date = new Date(messageExchange.getTimestamp())
use(groovy.time.TimeCategory){
after24Hours = (date + 24.hours).format("yyyy-MM-dd'T'HH:mm:ss'Z'", TimeZone.getTimeZone('UTC'))
def date1 = Date.parse("yyyy-MM-dd'T'HH:mm:ss'Z'", dueDate)
def date2 = Date.parse("yyyy-MM-dd'T'HH:mm:ss'Z'", after24Hours)
TimeDuration difference = TimeCategory.minus(date2, date1)
log.info date1
log.info date2
assert difference < 2.minutes
}
The script seems to work and it does return an error only if the time is longer than the one I've set in the assertion.
Unfortunately I have another issue now.
For some reason, my date output looks like this:
Fri Oct 01 16:24:10 EEST 2021: INFO: Sat Oct 02 13:24:10 EEST 2021
Which is not the correct format. That date should appear in the Zulu format, after all when I parsed the dates that was the format that I used.
Am I missing something?

Answer 1

What could I do to allow some margin of error in the assertion, maybe
like a few seconds or even a couple of minutes?
Instead of asserting that they are equal, you could assert that the difference between them is less than a threshold that you get to define.

Answer 2

If you use something like AssertJ, and I'd recommend you do, then you can do something like the following:
assertThat(dueDate).isCloseTo(after24Hours, within(1, ChronoUnit.MINUTE));
This will give a small margin to the comparison of the dates, and should fix your issue.