Parsed test spec with 2 sessions

starting permutation: w1_fetch w2_fetch w1_commit w2_commit
step w1_fetch: 
    SELECT payload::text, priority
    FROM ulak.queue
    WHERE status = 'pending'
    ORDER BY priority DESC, created_at ASC
    LIMIT 2
    FOR UPDATE SKIP LOCKED;

payload               |priority
----------------------+--------
{"seq": 5, "prio": 10}|      10
{"seq": 3, "prio": 5} |       5
(2 rows)

step w2_fetch: 
    SELECT payload::text, priority
    FROM ulak.queue
    WHERE status = 'pending'
    ORDER BY priority DESC, created_at ASC
    LIMIT 2
    FOR UPDATE SKIP LOCKED;

payload              |priority
---------------------+--------
{"seq": 4, "prio": 5}|       5
{"seq": 1, "prio": 0}|       0
(2 rows)

step w1_commit: COMMIT;
step w2_commit: COMMIT;