import json,platform
from urllib.parse import parse_qs,urlencode
samples=['C++','A B','서울&부산','a=b','100%','']
rows=[]
for value in samples:
 raw='q='+value;encoded=urlencode({'q':value})
 rows.append(dict(input=value,raw_query=raw,raw_decoded=parse_qs(raw,keep_blank_values=True),encoded_query=encoded,encoded_decoded=parse_qs(encoded,keep_blank_values=True)))
assert rows[0]['raw_decoded']=={'q':['C  ']} and rows[0]['encoded_decoded']=={'q':['C++']}
assert all(r['encoded_decoded']=={'q':[r['input']]} for r in rows)
blank=dict(default=parse_qs('q='),preserved=parse_qs('q=',keep_blank_values=True),zero=parse_qs('q=0',keep_blank_values=True),duplicate=parse_qs('q=C%2B%2B&q=A+B',keep_blank_values=True))
payload=json.dumps(dict(kind='executed_local_stdlib_experiment',date='2026-10-23',python=platform.python_version(),scope='Python form-style query parsing, no browser, web server or external service tested.',rows=rows,blank=blank),ensure_ascii=False,indent=2)
import argparse
parser=argparse.ArgumentParser(description='Local URL query round-trip experiment; no network requests.')
parser.add_argument('--output')
args=parser.parse_args()
if args.output:
 with open(args.output,'x',encoding='utf-8') as target:target.write(payload+'\n')
else:print(payload)