test fetch_with_meta error handling

Author: lovasoa

tests/sql_test_files/it_works_fetch_with_meta_error.sql

@@ -0,0 +1,7 @@
+set res = sqlpage.fetch_with_meta('http://not-a-real-url');
+
+select 'text' as component,
+    case
+        when json_extract($res, '$.error') LIKE 'Request failed%' then 'It works !'
+        else 'Error! Got: ' || $res
+    end as contents;