Test also passed on my MBP with SQLite 3.22.0 and the following line

    rc = _pysqlite_seterror(bck_conn, NULL);

returns

    1 (SQLITE_ERROR)

with

    "SQL logic error"

Looging at https://www.sqlite.org/src/artifact?ln=on&name=faf17e60b43233c2, checkReadTransaction() returns

    sqlite3ErrorWithMsg(db, SQLITE_ERROR, "destination database is in use");
    return SQLITE_ERROR;

I've opened PR 6067 to skip the test under SQLite 3.8.7.1 for now.

Lele, could you take a look at this please? It's almost 4 am here I won't be able to work on this in the next 10-15 hours.