Goal

Ensure that we have a CI test that checks that upgrades between PostgreSQL versions work correctly.

Background

The numeric format changed between PG13 and PG14 to include infinities (postgres/postgres@a57d312), which means that the serialized format that is used by continuous aggregates will not work after upgrading to PG14.

Problem

There are no upgrade tests that tests that the same result if produced after upgrading to a new PostgreSQL version.

Proposal

Use the existing upgrade tests between TimescaleDB versions and test that they generate the same result after running pg_upgrade when using the same TimescaleDB version.