How to connect to localhost with postgres_fdw?

Question

The idea is that I have local database named northwind, and with postgres_fdw I want to connect with another database named test on lo

Answer 1

After many attempts probably I found a proper way to connect:

CREATE SERVER app_db 
FOREIGN DATA WRAPPER postgres_fdw 
OPTIONS (dbname 'test', port '5432', host 'localhost');

Then:

CREATE USER MAPPING for postgres
SERVER app_db 
OPTIONS (user 'postgres', password 'postgres');

And then:

CREATE FOREIGN TABLE groups
(
  id serial NOT NULL,
  name character varying(255) NOT NULL,
  version integer DEFAULT 0
)
 SERVER app_db OPTIONS (schema_name 'public', table_name 'groups')

But is there a solution to check if it's really "remote" connection? Because servers are on the same localhost and I don't know if I can be sure.