Parsed test spec with 3 sessions

starting permutation: s2rx s2ry s1ry s1wy s1c s3r s2wx s2c s3c
step s2rx: SELECT balance FROM bank_account WHERE id = 'X';
balance
-------
      0
(1 row)

step s2ry: SELECT balance FROM bank_account WHERE id = 'Y';
balance
-------
      0
(1 row)

step s1ry: SELECT balance FROM bank_account WHERE id = 'Y';
balance
-------
      0
(1 row)

step s1wy: UPDATE bank_account SET balance = 20 WHERE id = 'Y';
step s1c: COMMIT;
step s3r: SELECT id, balance FROM bank_account WHERE id IN ('X', 'Y') ORDER BY id;
id|balance
--+-------
X |      0
Y |     20
(2 rows)

step s2wx: UPDATE bank_account SET balance = -11 WHERE id = 'X';
step s2c: COMMIT;
step s3c: COMMIT;