collect-v8-coverage 1.0.3: collect v8 code coverage with CoverageInstrumenter

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: collect v8 code coverage with CoverageInstrumenter
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/collect-v8-coverage@1.0.3
Demonstrate these symbols/APIs:
  - CoverageInstrumenter

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:c74a49f0cc61223cdb1f38b5ed445fa09b525e1831d6a80b3e3ec417cfb30d1c","contract":["CoverageInstrumenter initializes with inspector session capabilities","CoverageInstrumenter startInstrumenting connects inspector session and enables precise coverage","CoverageInstrumenter stopInstrumenting returns script coverage array containing function ranges and invocation counts","CoverageInstrumenter stopInstrumenting disables coverage tracking and profiler session"],"goal":"collect v8 code coverage with CoverageInstrumenter","kind":"HOW","packages":["pkg:npm/collect-v8-coverage@1.0.3"],"schemaVersion":1,"symbols":["CoverageInstrumenter"]},"contractCommand":["node","test/contract.mjs"],"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/collect-v8-coverage@1.0.3"],"schemaVersion":1,"subject":"pkg:npm/collect-v8-coverage@1.0.3","symbols":["CoverageInstrumenter"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-collect-v8-coverage",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-collect-v8-coverage",
      "version": "1.0.0",
      "dependencies": {
        "collect-v8-coverage": "1.0.3"
      }
    },
    "node_modules/collect-v8-coverage": {
      "version": "1.0.3",
      "resolved": "https://registry.npmjs.org/collect-v8-coverage/-/collect-v8-coverage-1.0.3.tgz",
      "integrity": "sha512-1L5aqIkwPfiodaMgQunkF1zRhNqifHBmtbbbxcr6yVxxBnliw4TDOW6NxpO8DJLgJ16OT+Y4ztZqP6p/FtXnAw==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-collect-v8-coverage",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "dependencies": {
    "collect-v8-coverage": "1.0.3"
  }
}

{
  "schemaVersion": 1,
  "goal": "collect v8 code coverage with CoverageInstrumenter",
  "kind": "HOW",
  "packages": [
    "pkg:npm/collect-v8-coverage@1.0.3"
  ],
  "symbols": [
    "CoverageInstrumenter"
  ]
}

import assert from 'node:assert/strict';
import { CoverageInstrumenter } from 'collect-v8-coverage';

// 1. CoverageInstrumenter initializes with inspector session capabilities
{
  const instrumenter = new CoverageInstrumenter();
  assert.ok(instrumenter instanceof CoverageInstrumenter);
  assert.equal(typeof instrumenter.startInstrumenting, 'function');
  assert.equal(typeof instrumenter.stopInstrumenting, 'function');
}

// 2. CoverageInstrumenter startInstrumenting connects inspector session and enables precise coverage
// 3. CoverageInstrumenter stopInstrumenting returns script coverage array containing function ranges and invocation counts
{
  const instrumenter = new CoverageInstrumenter();
  await instrumenter.startInstrumenting();

  function sampleFunction(a, b) {
    if (a > b) {
      return a * 2;
    }
    return b * 2;
  }

  const result = sampleFunction(10, 5);
  assert.equal(result, 20);

  const coverage = await instrumenter.stopInstrumenting();
  assert.ok(Array.isArray(coverage));
  assert.ok(coverage.length > 0);

  for (const script of coverage) {
    assert.equal(typeof script.scriptId, 'string');
    assert.equal(typeof script.url, 'string');
    assert.ok(Array.isArray(script.functions));
    for (const fn of script.functions) {
      assert.equal(typeof fn.functionName, 'string');
      assert.ok(Array.isArray(fn.ranges));
      assert.equal(typeof fn.isBlockCoverage, 'boolean');
      for (const range of fn.ranges) {
        assert.equal(typeof range.startOffset, 'number');
        assert.equal(typeof range.endOffset, 'number');
        assert.equal(typeof range.count, 'number');
      }
    }
  }

  const contractCoverage = coverage.find(item => item.url && item.url.includes('contract.mjs'));
  assert.ok(contractCoverage, 'expected coverage to include contract.mjs');
  const targetFn = contractCoverage.functions.find(fn => fn.functionName === 'sampleFunction');
  assert.ok(targetFn, 'expected coverage to record sampleFunction');
  assert.ok(targetFn.ranges.length > 0);
  assert.equal(targetFn.ranges[0].count, 1);
}

// 4. CoverageInstrumenter stopInstrumenting disables coverage tracking and profiler session
{
  const instrumenter = new CoverageInstrumenter();
  await instrumenter.startInstrumenting();
  const coverage = await instrumenter.stopInstrumenting();
  assert.ok(Array.isArray(coverage));
}

console.log('Contract tests passed successfully.');