Small tip when repeatedly doing upgrade testing

Suppose you want to test upgrading your software from version x to y. This often includes updates of database schemas, tables and content.

The obvious way to do this is

do {
  install version x
  quit x
  install version y
  verify upgrade
} while (upgrade was bad)

The install version x step here is usually time consuming and involves UI interactions.

A better approach here is to

install version x
create a db backup
verified = false
while (not verified )  {
  install version y
  if ( upgrade good )
      verified = true
  else
      install db backup
}

With PostgreSQL taking a backup would look like this:

pg_dump -f outfile -b -C dbname

e.g.:

pg_dump -f ~/jon231.dump -b -C jon231

and then the re-install:

pg_restore outfile

e.g.:

pg_restore ~/jon231.dump