mimic-response 1.0.1

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:npm/mimic-response@1.0.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/mimic-response@1.0.1
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:b52b588f869123948725828bace9ce17faaf6ed480eab80e4a3344f39efaf024","constraints":{"executionContext":"node"},"contract":["mimicResponse(fromStream, toStream) copies standard HTTP response properties including statusCode, statusMessage, headers, and httpVersion from source to target stream","mimicResponse(fromStream, toStream) copies custom properties and keys from source stream to target stream","mimicResponse(fromStream, toStream) binds functions from source stream to source stream when copied to target stream","mimicResponse(fromStream, toStream) does not overwrite properties that already exist on the target stream","mimicResponse(fromStream, toStream) ensures known response properties are defined on target stream even when undefined on source"],"goal":"verify pkg:npm/mimic-response@1.0.1","kind":"HOW","packages":["pkg:npm/mimic-response@1.0.1"],"schemaVersion":1},"contractCommand":["node","test/contract.js"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/mimic-response@1.0.1"],"schemaVersion":1,"subject":"pkg:npm/mimic-response@1.0.1","verifierAdapter":"node-typescript@1"}

{
  "name": "csx-sample-mimic-response",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "csx-sample-mimic-response",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "mimic-response": "1.0.1"
      }
    },
    "node_modules/mimic-response": {
      "version": "1.0.1",
      "resolved": "https://registry.npmjs.org/mimic-response/-/mimic-response-1.0.1.tgz",
      "integrity": "sha512-j5EctnkH7amfV/q5Hgmoal1g2QHFJRraOtmx0JpIqkxhBhI/lJSl1nMpQ45hVarwNETOoWEimndZ4QK0RHxuxQ==",
      "license": "MIT",
      "engines": {
        "node": ">=4"
      }
    }
  }
}

{
  "name": "csx-sample-mimic-response",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification for mimic-response",
  "main": "test/contract.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "mimic-response": "1.0.1"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/mimic-response@1.0.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/mimic-response@1.0.1"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

const assert = require('assert');
const { PassThrough } = require('stream');
const mimicResponse = require('mimic-response');

async function runTests() {
  // Test 1: mimicResponse(fromStream, toStream) copies standard HTTP response properties including statusCode, statusMessage, headers, and httpVersion from source to target stream
  {
    const fromStream = new PassThrough();
    fromStream.statusCode = 200;
    fromStream.statusMessage = 'OK';
    fromStream.headers = { 'content-type': 'application/json', 'content-length': '123' };
    fromStream.httpVersion = '1.1';
    fromStream.rawHeaders = ['Content-Type', 'application/json', 'Content-Length', '123'];

    const toStream = new PassThrough();
    mimicResponse(fromStream, toStream);

    assert.strictEqual(toStream.statusCode, 200, 'statusCode should match');
    assert.strictEqual(toStream.statusMessage, 'OK', 'statusMessage should match');
    assert.deepStrictEqual(toStream.headers, { 'content-type': 'application/json', 'content-length': '123' }, 'headers should match');
    assert.strictEqual(toStream.httpVersion, '1.1', 'httpVersion should match');
    assert.deepStrictEqual(toStream.rawHeaders, ['Content-Type', 'application/json', 'Content-Length', '123'], 'rawHeaders should match');
  }

  // Test 2: mimicResponse(fromStream, toStream) copies custom properties and keys from source stream to target stream
  {
    const fromStream = new PassThrough();
    fromStream.customData = 'test-value';
    fromStream.numericId = 42;
    fromStream.meta = { key: 'val' };

    const toStream = new PassThrough();
    mimicResponse(fromStream, toStream);

    assert.strictEqual(toStream.customData, 'test-value', 'customData should be copied');
    assert.strictEqual(toStream.numericId, 42, 'numericId should be copied');
    assert.deepStrictEqual(toStream.meta, { key: 'val' }, 'meta object should be copied');
  }

  // Test 3: mimicResponse(fromStream, toStream) binds functions from source stream to source stream when copied to target stream
  {
    const fromStream = new PassThrough();
    fromStream.getStreamContext = function () {
      return this === fromStream;
    };

    const toStream = new PassThrough();
    mimicResponse(fromStream, toStream);

    assert.strictEqual(typeof toStream.getStreamContext, 'function', 'copied property should be a function');
    assert.strictEqual(toStream.getStreamContext(), true, 'bound function this should refer to fromStream');
  }

  // Test 4: mimicResponse(fromStream, toStream) does not overwrite properties that already exist on the target stream
  {
    const fromStream = new PassThrough();
    fromStream.existingProp = 'from-source';
    fromStream.statusCode = 500;

    const toStream = new PassThrough();
    toStream.existingProp = 'original-target';
    toStream.statusCode = 200;

    mimicResponse(fromStream, toStream);

    assert.strictEqual(toStream.existingProp, 'original-target', 'existing property on target should not be overwritten');
    assert.strictEqual(toStream.statusCode, 200, 'existing statusCode on target should not be overwritten');
  }

  // Test 5: mimicResponse(fromStream, toStream) ensures known response properties are defined on target stream even when undefined on source
  {
    const fromStream = new PassThrough();
    const toStream = new PassThrough();

    mimicResponse(fromStream, toStream);

    assert.strictEqual('statusCode' in toStream, true, 'statusCode should exist in toStream');
    assert.strictEqual('statusMessage' in toStream, true, 'statusMessage should exist in toStream');
    assert.strictEqual('headers' in toStream, true, 'headers should exist in toStream');
    assert.strictEqual('rawHeaders' in toStream, true, 'rawHeaders should exist in toStream');
    assert.strictEqual('httpVersion' in toStream, true, 'httpVersion should exist in toStream');
    assert.strictEqual('socket' in toStream, true, 'socket should exist in toStream');
  }

  console.log('All mimic-response contract assertions passed successfully.');
}

runTests().catch((err) => {
  console.error('Contract test failed:', err);
  process.exit(1);
});