It's long we need to have binary upgrade tests in our CI. One example
is #6935 (and others) that can be prevented if we have such kind of
test in our CI.
To implement the `pg_upgrade` test we used the python Testing Framework
for PostgreSQL (https://github.com/postgrespro/testgres).
Unfortunately the testing framework don't have the ability to retain the
pg_upgrade log files after a successful execution, then we created a PR
to make it possible and we'll use this patched version until we get the
code merged and released on upstream.
https://github.com/postgrespro/testgres/pull/125Closes#3868#4428
