To reproduce this testdata, run sqlite3 and execute:
PRAGMA journal_mode = WAL;
CREATE TABLE t (x);
INSERT INTO t (x) VALUES (1);
INSERT INTO t (x) VALUES (2);
And copy & split the WAL into segments:
sl3 split -o generations/0000000000000000/wal/00000000 db-wal
cp db-wal 00000000.wal
Then execute:
PRAGMA wal_checkpoint(TRUNCATE);
INSERT INTO t (x) VALUES (3);
And split again:
sl3 split -o generations/0000000000000000/wal/00000001 db-wal
cp db-wal 00000001.wal
Then execute:
PRAGMA wal_checkpoint(TRUNCATE);
INSERT INTO t (x) VALUES (4);
INSERT INTO t (x) VALUES (5);
And split again:
sl3 split -o generations/0000000000000000/wal/00000002 db-wal
cp db-wal 00000002.wal
Finally, remove the original database files:
rm db*