--
-- 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 event is still
-- visible through macavity_status() afterwards.
--
-- before_commit is the point used for counting, because its matching hits
-- are transaction ends and this file controls those explicitly.  While a
-- before_commit event 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 the event 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
(1 row)

SELECT state, occurrence, hits, remaining FROM macavity_status();	-- 0 / 1
 state | occurrence | hits | remaining 
-------+------------+------+-----------
 armed |          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.
-- the event is completed now, and still described in full.
SELECT * FROM macavity_status();
 event_id |     point     | action | occurrence | hits | remaining |   state   
----------+---------------+--------+------------+------+-----------+-----------
        1 | before_commit | error  |          1 |    1 |         0 | completed
(1 row)

SELECT macavity_reset();
 macavity_reset 
----------------
              1
(1 row)

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

COMMIT;																-- hit 1
BEGIN;
SELECT state, hits, remaining FROM macavity_status();				-- 1 / 1
 state | hits | remaining 
-------+------+-----------
 armed |    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 event_id, point, occurrence, hits, remaining, state FROM macavity_status();
 event_id |     point     | occurrence | hits | remaining |   state   
----------+---------------+------------+------+-----------+-----------
        1 | before_commit |          2 |    2 |         0 | completed
(1 row)

-- Reinstating the completed event by ID starts its counters again from 0,
-- with the same ID and configuration.  Watch them after every hit of a
-- second run to completion.
BEGIN;
SELECT macavity_arm(1);
 macavity_arm 
--------------
 t
(1 row)

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

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

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

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

SELECT macavity_reset();
 macavity_reset 
----------------
              1
(1 row)

-- occurrence = 3: check hits and remaining after every matching hit.
BEGIN;
SELECT macavity_arm('before_commit', 'error', 3);
 macavity_arm 
--------------
            1
(1 row)

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

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

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

COMMIT;																-- hit 2
BEGIN;
SELECT state, hits, remaining FROM macavity_status();				-- 2 / 1
 state | hits | remaining 
-------+------+-----------
 armed |    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 * FROM macavity_status();
 event_id |     point     | action | occurrence | hits | remaining |   state   
----------+---------------+--------+------------+------+-----------+-----------
        1 | before_commit | error  |          3 |    3 |         0 | completed
(1 row)

-- A reset returns the session to an empty registry, with no trace of the
-- completed event.
SELECT macavity_reset();
 macavity_reset 
----------------
              1
(1 row)

SELECT * FROM macavity_status();
 event_id | point | action | occurrence | hits | remaining | state 
----------+-------+--------+------------+------+-----------+-------
(0 rows)

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

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

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

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

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

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

ROLLBACK;
-- A disarmed event keeps the counters it had reached ...
BEGIN;
SELECT macavity_arm(1);
 macavity_arm 
--------------
 t
(1 row)

COMMIT;																-- hit 1
BEGIN;
SELECT macavity_disarm(1);
 macavity_disarm 
-----------------
 t
(1 row)

ROLLBACK;
SELECT event_id, state, hits, remaining FROM macavity_status();		-- 1 / 1
 event_id |  state   | hits | remaining 
----------+----------+------+-----------
        1 | disarmed |    1 |         1
(1 row)

-- ... until it is reinstated, which resets them.
BEGIN;
SELECT macavity_arm(1);
 macavity_arm 
--------------
 t
(1 row)

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

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

ROLLBACK;
SELECT macavity_reset();
 macavity_reset 
----------------
              1
(1 row)

-- 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
(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 state, hits, remaining FROM macavity_status();
 state | hits | remaining 
-------+------+-----------
 armed |    2 |         3
(1 row)

SELECT macavity_reset();
 macavity_reset 
----------------
              1
(1 row)

SELECT * FROM macavity_status();
 event_id | point | action | occurrence | hits | remaining | state 
----------+-------+--------+------------+------+-----------+-------
(0 rows)