slachiewicz opened a new pull request, #12679:
URL: https://github.com/apache/maven/pull/12679
`MonotonicClockTest.testElapsedTimeConsistency` fails intermittently on CI,
on PRs that have nothing to do with the clock (most recently on the Dependabot
xmlunit bump, #12671):
```
[ERROR] org.apache.maven.api.MonotonicClockTest.testElapsedTimeConsistency
org.opentest4j.AssertionFailedError: Elapsed time should match calculated
duration between start and now ==> expected: but was:
```
### Cause
The test took two *separate* samples of the monotonic source and required
them to agree within 1ms:
```java
Instant now = clock.instant(); // nanoTime read #1
Duration elapsed = clock.elapsedTime(); // nanoTime read #2, taken later
Duration calculated = Duration.between(clock.startInstant(), now);
assertTrue(Math.abs(elapsed.toMillis() - calculated.toMillis()) <= 1, ...);
```
Normally the two reads are microseconds apart, so the 1ms budget holds. But
a GC pause or a scheduler deschedule between them is enough to blow it on a
loaded CI agent, and `toMillis()` truncation eats part of the budget as well.
Nothing is wrong with `MonotonicClock` when this fires — the test is simply
asserting a wall-clock timing bound.
### Fix
Sandwich the `instant()` sample between two `elapsedTime()` samples and
assert the ordering instead:
```java
Duration before = clock.elapsedTime();
Instant now = clock.instant();
Duration after = clock.elapsedTime();
Duration calculated = Duration.between(clock.startInstant(), now);
assertTrue(calculated.compareTo(before) >= 0 && calculated.compareTo(after)
<= 0, ...);
```
All three values derive from the same `System.nanoTime()` base, so `before
<= calculated <= after` holds no matter how long the JVM stalls between the
calls. No tolerance and no timing assumption, and the assertion still catches a
genuine inconsistency between `instant()` and `elapsedTime()` — which is what
the test is there for. The failure message now prints all three durations.
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