#!/usr/bin/env python3
"""Standalone synthetic fixture; standard library only. No network, credentials or user paths."""
import json, math, statistics, sys, platform, datetime

x=[[540,600],[570,630],[630,660],[720,735]]
def union(a):
 if any(e<s for s,e in a):raise ValueError('end before start')
 out=[]
 for s,e in sorted(a):
  if s==e:continue
  if out and s<=out[-1][1]:out[-1][1]=max(e,out[-1][1])
  else:out.append([s,e])
 return out
m=union(x);bad=False
try:union([[600,540]])
except ValueError:bad=True
result={'inputMinutes':x,'naiveSum':sum(e-s for s,e in x),'mergedHalfOpen':m,'unionMinutes':sum(e-s for s,e in m),'nested':union(x+[[550,560]]),'empty':union([]),'zeroLength':union([[600,600]]),'invalidBlocked':bad,'idempotent':union(m)==m,'reorderedSame':union(list(reversed(x)))==m}
assert result['naiveSum']==165 and result['unionMinutes']==135 and result['nested']==m

print(json.dumps({"fixtureCreatedOn":"2026-10-15","executedAt":datetime.datetime.now(datetime.timezone.utc).isoformat(),"synthetic":True,"runtime":platform.python_version(),"result":result},ensure_ascii=False,indent=2))