Uses anti_id computed column to make test case clearer

test/Feature/QuerySpec.hs

@@ -134,7 +134,7 @@ spec =
         [json| [{"id":1},{"id":2},{"id":3},{"id":4},{"id":5},{"id":6},{"id":7},{"id":8},{"id":9},{"id":10},{"id":11},{"id":12},{"id":13},{"id":14},{"id":15}] |]
 
     it "order by computed column" $
-      get "/items?order=always_true.asc,id.asc" `shouldRespondWith`
+      get "/items?order=anti_id.desc" `shouldRespondWith`
         [json| [{"id":1},{"id":2},{"id":3},{"id":4},{"id":5},{"id":6},{"id":7},{"id":8},{"id":9},{"id":10},{"id":11},{"id":12},{"id":13},{"id":14},{"id":15}] |]
 
     it "matches filtering nested items" $

test/fixtures/schema.sql

@@ -462,6 +462,11 @@ CREATE FUNCTION public.always_true(test.items) RETURNS boolean
 
 ALTER FUNCTION public.always_true(test.items) OWNER TO postgrest_test;
 
+CREATE FUNCTION public.anti_id(test.items) RETURNS bigint
+LANGUAGE sql STABLE
+AS $$ SELECT $1.id * -1 $$;
+
+ALTER FUNCTION public.anti_id(test.items) OWNER TO postgrest_test;
 
 
 ALTER TABLE ONLY authors_only