Function gc_collapses_ops_below_frontier

nodedb/tests/array_sync_gc.rs:75–101

()

/// Ops at or above the frontier survive.
#[test]
fn gc_collapses_ops_below_frontier() {
    let log = InMemoryOpLog::new();
    for ms in [10u64, 20, 30, 40] {
        log.append(&make_op("arr", ms, 1)).expect("append");
    }

    let mut acks = AckVector::new();
    acks.record(rep(1), hlc(25, 1)); // frontier = 25

    let sink = MockSnapshotSink::new();
    let report = collapse_below(&log, &acks, &sink, |array, frontier| {
        Ok(Some(dummy_snapshot(array, frontier)))
    })
    .expect("collapse_below");

    // Ops strictly < 25: ms=10, ms=20 → 2 ops dropped.
    assert_eq!(report.frontier, hlc(25, 1));
    assert_eq!(
        report.ops_dropped, 2,
        "ops at ms=10 and ms=20 must be dropped"
    );
    assert_eq!(
        report.snapshots_written, 1,
        "one snapshot written for 'arr'"
    );
    assert_eq!(log.len().expect("len"), 2, "ms=30 and ms=40 must remain");
}

/// Multiple acks from different replicas: the frontier is the minimum.
#[test]