API 필드 이름 변경: HTTP 200이어도 깨지는 6개 조합과 안전한 배포 순서

/** Run: node contract.cjs. No dependencies, AI calls or external network.
 * The disposable HTTP fixture deliberately includes invalid server contracts.
 * A failed contract is an expected observation; assertions verify the matrix.
 */
const http = require('node:http');
const assert = require('node:assert/strict');
const fs = require('node:fs');
const path = require('node:path');
const fixtures = {
  old: {price:12000},
  bridge: {price:12000, amount:12000},
  next: {amount:12000},
  conflict: {price:12000, amount:13000},
  strings: {price:'12000', amount:'12000'}
};
// Presence alone is insufficient. This small KRW contract requires integer values.
function consume(body, field) {
  if (!Object.hasOwn(body,field)) return {ok:false,reason:'MISSING_FIELD'};
  if (!Number.isSafeInteger(body[field]) || body[field]<0) return {ok:false,reason:'INVALID_TYPE'};
  // During the bridge period both field names must mean the same amount.
  if (Object.hasOwn(body,'price') && Object.hasOwn(body,'amount') && body.price!==body.amount)
    return {ok:false,reason:'CONFLICTING_ALIASES'};
  return {ok:true,value:body[field]};
}
(async()=>{
  const server=http.createServer((req,res)=>{
    res.setHeader('Content-Type','application/json');
    res.end(JSON.stringify(fixtures[req.url.slice(1)]));
  });
  await new Promise(resolve=>server.listen(0,'127.0.0.1',resolve));
  const results=[];
  try {
    for(const [name,body] of Object.entries(fixtures)) for(const field of ['price','amount']) {
      const response=await fetch(`http://127.0.0.1:${server.address().port}/${name}`);
      const result=consume(await response.json(),field);
      const expected=name==='bridge'||(name==='old'&&field==='price')||(name==='next'&&field==='amount');
      assert.equal(response.status,200);
      assert.equal(result.ok,expected);
      results.push({server:name,consumer:field,http:response.status,...result});
    }
    assert.equal(consume({price:0,amount:0},'amount').value,0);
    assert.equal(consume({amount:null},'amount').ok,false);
    const output={environment:{node:process.version,host:'loopback only'},results,passedContracts:results.filter(x=>x.ok).length,failedContracts:results.filter(x=>!x.ok).length,assertions:22};
    fs.writeFileSync(path.join(__dirname,'results','contract.json'),JSON.stringify(output,null,2));
    console.log(JSON.stringify(output,null,2));
  } finally {await new Promise(resolve=>server.close(resolve));}
})().catch(error=>{console.error(error);process.exitCode=1});