pgTAP installation

Hi all,

I'm just tipping my toe into the water with pgTAP for the first time,
and must be doing something wrong - I can't seem to get it working.

I'm on Kubuntu Hirsute, and I've installed both PostgreSQL 13 and pgTAP
from apt.postgresql.org:

sudo apt install postgresql-13
sudo apt install postgresql-13-pgtap

Then I connected to my database and installed pgTAP there:

create extension pgtap;

And I can see it there:

gfc_booking6_dev=# \dx
List of installed extensions
Name | Version | Schema | Description
---------+---------+------------+------------------------------
pgtap | 1.1.0 | public | Unit testing for PostgreSQL
plpgsql | 1.0 | pg_catalog | PL/pgSQL procedural language
(2 rows)

However, when I try to use it, I get:

gfc_booking6_dev=# select * from noplan();
ERROR: function noplan() does not exist
LINE 1: select * from noplan();
^
HINT: No function matches the given name and argument types. You might
need to add explicit type casts.

Am I missing a step somewhere?

Many thanks in advance,

Ray.

--
Raymond O'Donnell // Galway // Ireland
ray(at)rodonnell(dot)ie