We will create a small arbitrary point dataset to feed into our function around which we will calculate the Voronoi diagram:

DROP TABLE IF EXISTS chp04.voronoi_test_points; 
CREATE TABLE chp04.voronoi_test_points 
( 
  x numeric, 
  y numeric 
) 
WITH (OIDS=FALSE); 
 
ALTER TABLE chp04.voronoi_test_points ADD COLUMN gid serial; 
ALTER TABLE chp04.voronoi_test_points ADD PRIMARY KEY (gid); 
 
INSERT INTO chp04.voronoi_test_points (x, y) 
  VALUES (random() * 5, random() * 7); 
INSERT INTO chp04.voronoi_test_points (x, y) 
  VALUES (random() * 2, random() * 8); 
INSERT INTO chp04.voronoi_test_points (x, y) 
  VALUES (random() * 10, random() * 4); 
INSERT INTO chp04.voronoi_test_points (x, y) 
  VALUES (random() * 1, random() * 15); 
INSERT INTO chp04.voronoi_test_points (x, y) 
  VALUES (random() * 4, random() * 9); 
INSERT INTO chp04.voronoi_test_points (x, y) 
  VALUES (random() * 8, random() * 3); 
INSERT INTO chp04.voronoi_test_points (x, y) 
  VALUES (random() * 5, random() * 3); 
INSERT INTO chp04.voronoi_test_points (x, y) 
  VALUES (random() * 20, random() * 0.1); 
INSERT INTO chp04.voronoi_test_points (x, y) 
  VALUES (random() * 5, random() * 7); 
 
SELECT AddGeometryColumn ('chp04','voronoi_test_points','the_geom',3734,'POINT',2); 
 
UPDATE chp04.voronoi_test_points 
  SET the_geom = ST_SetSRID(ST_MakePoint(x,y), 3734) 
  WHERE the_geom IS NULL
;