Parsed test spec with 3 sessions

starting permutation: s3_prep s1_group s3_parked s2_fill s2_wakeup s1_plain s1_group2 s3_shape s3_verify
injection_points_attach
-----------------------
                       
(1 row)

step s3_prep: VACUUM (FREEZE, ANALYZE) mces;
step s1_group: 
	SELECT groups, count FROM lion_index_count_group_stats('mces_go', true, 1::int2);
 <waiting ...>
step s3_parked: SELECT count(*) = 1 AS parked FROM pg_stat_activity WHERE wait_event_type = 'InjectionPoint' AND wait_event = 'lion-entry-scan-resumed';
parked
------
t     
(1 row)

step s2_fill: 
	BEGIN;
	INSERT INTO mces
	SELECT 100000 + i,
		   'g-' || lpad((i % 30)::text, 90, '0'),		-- existing g keys
		   'o-new-' || lpad(i::text, 86, '0'),			-- brand new o keys
		   repeat('y', 200)
	  FROM generate_series(1, 120) i;
	ROLLBACK;

step s2_wakeup: 
	/*
	 * Detach first, so that nothing can park at the point again, then
	 * release whoever is parked now.  How MANY times the point is reached is
	 * not fixed - the walk fires it once per leaf it consumes an entry from,
	 * and the split makes more leaves - but after this step nobody is waiting
	 * on it, which is all the permutation needs.
	 */
	SELECT injection_points_detach('lion-entry-scan-resumed');
	DO $$
	DECLARE n int; zero int := 0;
	BEGIN
		FOR i IN 1 .. 6000 LOOP
			SELECT count(*) INTO n FROM pg_stat_activity
			 WHERE wait_event = 'lion-entry-scan-resumed';
			IF n = 0 THEN
				zero := zero + 1;
				EXIT WHEN zero >= 10;
			ELSE
				zero := 0;
				BEGIN
					PERFORM injection_points_wakeup('lion-entry-scan-resumed');
				EXCEPTION WHEN OTHERS THEN NULL;
				END;
			END IF;
			PERFORM pg_sleep(0.01);
		END LOOP;
	END $$;

injection_points_detach
-----------------------
                       
(1 row)

step s1_group: <... completed>
groups|count
------+-----
    30| 6000
(1 row)

step s1_plain: 
	SELECT count(*) AS groups, sum(c) AS count
	  FROM (SELECT g, count(*) AS c FROM mces GROUP BY g) x;

groups|count
------+-----
    30| 6000
(1 row)

step s1_group2: 
	SELECT groups, count FROM lion_index_count_group_stats('mces_go', true, 2::int2);

groups|count
------+-----
    10| 6000
(1 row)

step s3_shape: 
	SELECT leaf_pages > 1 AS the_shared_leaf_really_split,
		   directory_height > 0 AS the_root_really_moved
	  FROM lion_index_stats('mces_go') WHERE attno = 1;
	SELECT attno, entries FROM lion_index_stats('mces_go') ORDER BY attno;

the_shared_leaf_really_split|the_root_really_moved
----------------------------+---------------------
t                           |t                    
(1 row)

attno|entries
-----+-------
    1|     30
    2|    130
(2 rows)

step s3_verify: SELECT lion_index_verify('mces_go', true);
lion_index_verify
-----------------
                 
(1 row)