Improve query findFollowsByTarget & add tests

src/main/resources/sql/functions/follow/find_follows_article_by_target.sql

@@ -1,20 +1,21 @@
 create or replace function find_follows_article_by_target(
     _target_id uuid,
-    "limit" int default 50,
-    "offset" int default 0,
-    out resource json,
-    out total int
+    _limit int default 50,
+    _start_id uuid default null,
+    out resource json
 ) language plpgsql as
 $$
 declare
     _version_id uuid = (select version_id from article where id = _target_id);
+    _start_at timestamp default '2000-01-01 00:00:00'::timestamp;
+    _article_creator_id uuid = (select created_by_id from article where id = _target_id);
 begin
-    select json_agg(t), (
-        select count(f.id)
-        from follow f
-        join article a on f.target_id = a.id
-        where a.version_id = _version_id)
-    into resource, total
+    if _start_id is not null then
+        select created_at into _start_at from follow where id = _start_id;
+    end if;
+
+    select json_agg(t)
+    into resource
     from (
         select
             f.id,
@@ -22,11 +23,17 @@ begin
             f.target_reference,
             json_build_object('id', f.target_id) as target,
             find_citizen_by_id_with_user(f.created_by_id) as created_by
-        from follow_article as f
-        join article a on f.target_id = a.id
-        where a.version_id = _version_id
+        from follow as f
+        left join article a on f.target_reference = 'article'::regclass and f.target_id = a.id
+        where (
+            (f.target_reference = 'article'::regclass and a.version_id = _version_id)
+            or
+            (f.target_reference = 'citizen'::regclass and f.target_id = _article_creator_id)
+          )
+          and f.created_at >= _start_at
+          and (_start_id is null or f.id != _start_id)
         order by f.created_at
-        limit "limit" offset "offset"
+        limit _limit
     ) as t;
 end
 $$;