Facility for cross-version tests of pg_upgrade
==============================================

This sub-directory contains a set of full dumps of the regression database
that can be used as a base for cross-version upgrade tests, using the new
TAP facility introduced in v15~.  Those dumps are taken using pg_dumpall
installed in their original version (e.g. a dump from PostgreSQL 12 has
been taken with pg_dumpall from v12) so as they can be loaded in the past
clustered data is upgraded from.  The dumps are named $BRANCH_NAME.dump,
to point to the stable branch they are associated with.

The dumps saved in this directory can be used as follows in the TAP test
facility, invoked from src/bin/pg_upgrade/ of the new source repository:

    export olddump=/path/to/dump/${OLD_BRANCH}.dump
    export oldinstall=/path/to/install/$OLD_BRANCH
    make check

The dumps have been changed to work under the following assumptions to
avoid any dependencies with a source code tree:

  * autoinc and refint should be installed within postgresql/ as indicated
  by "pg_config --libdir", so as they can be loaded in CREATE FUNCTION with
  "$libdir/postgresql/library.so".
  * regress.so, a library created in the code tree in src/test/regress/ is
  not installed by PostgreSQL, but assumed to be in "$libdir/regress.so".

At the end, this configuration is only dependent on an installation path
and the dumps in this folder.
