Unpredictable behavior around `during` and `atMost` of Awaitility - testing

Question

While I was testing Kafka I end up with some issues around Awaitility. The goal was to test that Kafka topic doesn't contain the new records for a specified time. This is the simplified scratch of my test but it shows the problem. I expect that ConditionTimeoutException doesn't throw in this case. But it does.
public static void main(String[] args) {
List<String> list = new ArrayList<>();
await("wait").during(5_000, TimeUnit.MILLISECONDS).atMost(5_000, TimeUnit.MILLISECONDS)
.pollInterval(100, TimeUnit.MILLISECONDS)
.until(() -> list, List::isEmpty);
}
I increased the atMost timeout to 5000 + pollInterval -> 5100 but still end up with exception. On my local machine throwing exception was stoped closed the value of atMost timeout of 5170-5180.
Should I keep something in mind? Or may the test isn't correct?

Answer 1

In your case, you want to ensure, that the list is still empty after 5 seconds. Just remove "atMost" part. This code should work:
public static void main(String[] args) {
List<String> list = new ArrayList<>();
await("wait").during(5_000, TimeUnit.MILLISECONDS)
.pollInterval(100, TimeUnit.MILLISECONDS)
.until(() -> list, List::isEmpty);
}
If you want to use "during" with "atMost" together, ensure, that atMost time is greater:
public static void main(String[] args) {
List<String> list = new ArrayList<>();
await("wait").during(5_000, TimeUnit.MILLISECONDS).atMost(5_500, TimeUnit.MILLISECONDS)
.pollInterval(100, TimeUnit.MILLISECONDS)
.until(() -> list, List::isEmpty);
}