--
-- macavity: hits/remaining semantics.
--
-- The invariant under test: a matching fault-point hit is recorded BEFORE
-- the configured action runs, so the hit that fired the fault is still
-- visible through macavity_status() afterwards.
--
-- before_commit is the point used for counting, because its matching events
-- are transaction ends and this file controls those explicitly.  While a
-- before_commit fault is armed, every status query is therefore wrapped in
-- BEGIN ... ROLLBACK: an abort is not a commit, so reading the counters
-- does not disturb them.  Once a fault has fired, nothing is armed and
-- plain autocommit statements are safe again.
--
-- occurrence = 1: the first matching hit fires.
BEGIN;
SELECT macavity_arm('before_commit', 'error', 1);
 macavity_arm 
--------------
 
(1 row)

SELECT armed, occurrence, hits, remaining FROM macavity_status();	-- 0 / 1
 armed | occurrence | hits | remaining 
-------+------------+------+-----------
 t     |          1 |    0 |         1
(1 row)

COMMIT;																-- hit 1: fires
ERROR:  macavity: injected error at fault point "before_commit"
-- the hit was counted before the error was raised: hits 1, remaining 0.
-- armed is false now, but the spent fault is still described.
SELECT armed, point, action, occurrence, hits, remaining FROM macavity_status();
 armed |     point     | action | occurrence | hits | remaining 
-------+---------------+--------+------------+------+-----------
 f     | before_commit | error  |          1 |    1 |         0
(1 row)

SELECT macavity_disarm();
 macavity_disarm 
-----------------
 
(1 row)

-- occurrence = 2: the first hit only counts; the second fires.
BEGIN;
SELECT macavity_arm('before_commit', 'error', 2);
 macavity_arm 
--------------
 
(1 row)

COMMIT;																-- hit 1
BEGIN;
SELECT armed, hits, remaining FROM macavity_status();				-- 1 / 1
 armed | hits | remaining 
-------+------+-----------
 t     |    1 |         1
(1 row)

ROLLBACK;
BEGIN;
SELECT 1 AS second_transaction;
 second_transaction 
--------------------
                  1
(1 row)

COMMIT;																-- hit 2: fires
ERROR:  macavity: injected error at fault point "before_commit"
SELECT armed, point, occurrence, hits, remaining FROM macavity_status();
 armed |     point     | occurrence | hits | remaining 
-------+---------------+------------+------+-----------
 f     | before_commit |          2 |    2 |         0
(1 row)

-- Arming again replaces the spent fault's counters with a fresh 0.
-- occurrence = 3: check hits and remaining after every matching hit.
BEGIN;
SELECT macavity_arm('before_commit', 'error', 3);
 macavity_arm 
--------------
 
(1 row)

SELECT armed, hits, remaining FROM macavity_status();				-- 0 / 3
 armed | hits | remaining 
-------+------+-----------
 t     |    0 |         3
(1 row)

COMMIT;																-- hit 1
BEGIN;
SELECT armed, hits, remaining FROM macavity_status();				-- 1 / 2
 armed | hits | remaining 
-------+------+-----------
 t     |    1 |         2
(1 row)

ROLLBACK;
BEGIN;
SELECT 1 AS transaction_two;
 transaction_two 
-----------------
               1
(1 row)

COMMIT;																-- hit 2
BEGIN;
SELECT armed, hits, remaining FROM macavity_status();				-- 2 / 1
 armed | hits | remaining 
-------+------+-----------
 t     |    2 |         1
(1 row)

ROLLBACK;
BEGIN;
SELECT 1 AS transaction_three;
 transaction_three 
-------------------
                 1
(1 row)

COMMIT;																-- hit 3: fires
ERROR:  macavity: injected error at fault point "before_commit"
SELECT armed, point, action, occurrence, hits, remaining FROM macavity_status();
 armed |     point     | action | occurrence | hits | remaining 
-------+---------------+--------+------------+------+-----------
 f     | before_commit | error  |          3 |    3 |         0
(1 row)

-- An explicit disarm returns the session to the clear state: armed false
-- and every other column NULL, with no trace of the spent fault.
SELECT macavity_disarm();
 macavity_disarm 
-----------------
 
(1 row)

SELECT * FROM macavity_status();
 armed | point | action | occurrence | hits | remaining 
-------+-------+--------+------------+------+-----------
 f     |       |        |            |      |          
(1 row)

-- Events at other points, and aborts, are not matching events and do not
-- move the counters.
BEGIN;
SELECT macavity_arm('before_commit', 'error', 2);
 macavity_arm 
--------------
 
(1 row)

SELECT 1 AS statement_one;
 statement_one 
---------------
             1
(1 row)

SELECT 1 AS statement_two;
 statement_two 
---------------
             1
(1 row)

SELECT armed, hits, remaining FROM macavity_status();				-- still 0 / 2
 armed | hits | remaining 
-------+------+-----------
 t     |    0 |         2
(1 row)

ROLLBACK;															-- an abort, not a hit
BEGIN;
SELECT armed, hits, remaining FROM macavity_status();				-- still 0 / 2
 armed | hits | remaining 
-------+------+-----------
 t     |    0 |         2
(1 row)

SELECT macavity_disarm();
 macavity_disarm 
-----------------
 
(1 row)

ROLLBACK;
-- The counters are not transactional: a hit recorded inside a transaction
-- that later rolls back stays recorded.  That is what makes the counters
-- trustworthy after an injected error, which always aborts its transaction.
SELECT macavity_arm('executor_start', 'error', 5);
 macavity_arm 
--------------
 
(1 row)

BEGIN;
SELECT 1 AS hit_inside_doomed_transaction;
 hit_inside_doomed_transaction 
-------------------------------
                             1
(1 row)

ROLLBACK;
-- 2 hits: the rolled-back statement, plus this status query itself
SELECT armed, hits, remaining FROM macavity_status();
 armed | hits | remaining 
-------+------+-----------
 t     |    2 |         3
(1 row)

SELECT macavity_disarm();
 macavity_disarm 
-----------------
 
(1 row)

SELECT * FROM macavity_status();
 armed | point | action | occurrence | hits | remaining 
-------+-------+--------+------------+------+-----------
 f     |       |        |            |      |          
(1 row)