diff --git a/resources/functions/user/find_user_by_id.sql b/resources/functions/user/find_user_by_id.sql
index d5f8ffa..9833093 100644
--- a/resources/functions/user/find_user_by_id.sql
+++ b/resources/functions/user/find_user_by_id.sql
@@ -1,4 +1,4 @@
-create or replace procedure find_user_by_id(in id uuid, inout resource json) language plpgsql as
+create or replace function find_user_by_id(in id uuid, out resource json) language plpgsql as
 $$
 declare
     _id alias for id;
@@ -9,4 +9,4 @@ begin
 end;
 $$;
 
--- drop procedure if exists find_user_by_id(uuid, inout json);
\ No newline at end of file
+-- drop function if exists find_user_by_id(uuid, inout json);
\ No newline at end of file
diff --git a/resources/functions/user/find_user_by_username.sql b/resources/functions/user/find_user_by_username.sql
index c8c6e4b..717a643 100644
--- a/resources/functions/user/find_user_by_username.sql
+++ b/resources/functions/user/find_user_by_username.sql
@@ -1,4 +1,4 @@
-create or replace procedure find_user_by_username(in username text, inout resource json) language plpgsql as
+create or replace function find_user_by_username(in username text, out resource json) language plpgsql as
 $$
 declare
     _username alias for username;
@@ -9,4 +9,4 @@ begin
 end;
 $$;
 
--- drop procedure if exists find_user_by_username(text, inout json);
\ No newline at end of file
+-- drop function if exists find_user_by_username(text, out json);
\ No newline at end of file
diff --git a/resources/tests/user.sql b/resources/tests/user.sql
index cff7005..ec89e82 100644
--- a/resources/tests/user.sql
+++ b/resources/tests/user.sql
@@ -11,11 +11,11 @@ begin
     assert created_user->>'password' is not null, 'password must be generated';
 
     -- get user by there id and check the username is correct
-    call find_user_by_id((created_user->>'id')::uuid, selected_user);
-    assert selected_user->>'username' = 'george', 'username must be george';
+    select find_user_by_id((created_user->>'id')::uuid) into selected_user;
+    assert selected_user->>'username' = 'george', format('username must be george, %s instead', selected_user);
 
     -- get user by username and check the username is correct
-    call find_user_by_username(created_user->>'username', selected_user);
+    select find_user_by_username(created_user->>'username') into selected_user;
     assert selected_user->>'username' = 'george', 'username must be george';
 
     -- check if user exist with username and password and verify the reterned user