Re: [GENERAL] Global Variables?

[Eric Radman]

On Tue, Oct 11, 2011 at 04:26:47PM +0200, Alban Hertroys wrote:
> On 11 October 2011 16:06, Eric Radman  wrote:
> > When writing unit tests it's sometimes useful to stub functions such
> > as the current date and time
> 
> You could create a table for such "constants" and read your
> current-time from that table.
> 
> Additionally, I would put such stub functions in a separate schema and
> create a test role with that schema as the top of their search_path.
> 
> That way, you could even override system function implementations (and
> other definitions) and only have them apply to the role you're using
> for unit testing.

> CREATE ROLE unit_tester;
> CREATE SCHEMA unit_tests AUTHORIZATION unit_tester;
> SET search_path TO unit_tests, my_schema, public;
> 
> CREATE TABLE unit_test_parameters (
>current_time timestamp without time zone NOT NULL DEFAULT now()
> );

Excellent advice; this model works wonderfully. pg_catalog is normally
implicit, but you're right, system functions can be overridden by
setting the search path.


Eric Radman  |  http://eradman.com

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[GENERAL] Global Variables?

[Eric Radman]

When writing unit tests it's sometimes useful to stub functions such as
the current date and time

-- define mock functions
CREATE OR REPLACE FUNCTION _now() RETURNS timestamp with time zone AS $$
  BEGIN RETURN '2011-10-10 10:00'; END;
$$ LANGUAGE plpgsql;

-- define tables "accounts"
CREATE TABLE accounts (username varchar, expiration timestamp);

-- populate with sample data
COPY accounts FROM '/home/eradman/sample_accounts.txt';

-- define view "expired_accounts"
CREATE OR REPLACE VIEW expired_accounts AS SELECT * FROM accounts WHERE 
expiration < _now();

-- test views
SELECT assert(0, (SELECT count(*) FROM expired_accounts)::integer);

Is it possible to declare a global variable that can be referenced from
the user-defined function _now()? I'm looking for a means of abstraction
that allows me to avoid issuing CREATE OR REPLACE FUNCTION ... before
each assert()

current_time := '2012-01-01'::timestamp
SELECT assert(5, (SELECT count(*) FROM expired_accounts)::integer);

-- 
Eric Radman  |  http://eradman.com

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