If you’re using Postgresql with Rails 2.2, your testing database user needs to be a “superuser” for your tests to run. This is not a good thing. It’s the equivalent of running as root. But, if you’ve got a completely separate development/testing server it’s better than not being able to test at all.

If your postgres testing user isn’t a superuser, you’ll get errors like:

ActiveRecord::StatementInvalid: PGError: ERROR:  permission \
denied: "RI_ConstraintTrigger_17866" is a system trigger

You can create a postgres superuser thusly:

> su - postgres
> psql template1
> template1=# create user  your username superuser;

Update the testing stanza of your config/database.yml and you should be good to go.