@vitest/mocker 4.1.10: findMockRedirect

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 @vitest/mocker.findMockRedirect in pkg:npm/%40vitest/mocker@4.1.10
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40vitest/mocker@4.1.10
Demonstrate these symbols/APIs:
  - @vitest/mocker.findMockRedirect

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:b8a8d2a57e5c03ef314c19553dfeaedcdd51d65c8092dd7f8bf017fa05bd437d","contract":["findMockRedirect resolves __mocks__ file for external node module specifiers","findMockRedirect resolves __mocks__/\u003cdir\u003e/index file for directory-based external mocks","findMockRedirect resolves __mocks__ file for Node.js built-in module specifiers","findMockRedirect resolves adjacent __mocks__ file for local file paths","findMockRedirect returns null when no mock definition exists in __mocks__ directory"],"goal":"verify @vitest/mocker.findMockRedirect in pkg:npm/%40vitest/mocker@4.1.10","kind":"HOW","packages":["pkg:npm/%40vitest/mocker@4.1.10"],"schemaVersion":1,"symbols":["@vitest/mocker.findMockRedirect"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"npm","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/%40vitest/mocker@4.1.10"],"schemaVersion":1,"subject":"pkg:npm/%40vitest/mocker@4.1.10","symbols":["@vitest/mocker.findMockRedirect"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-vitest-mocker-find-mock-redirect",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-vitest-mocker-find-mock-redirect",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@vitest/mocker": "4.1.10"
      }
    },
    "node_modules/@jridgewell/sourcemap-codec": {
      "version": "1.6.0",
      "resolved": "https://registry.npmjs.org/@jridgewell/sourcemap-codec/-/sourcemap-codec-1.6.0.tgz",
      "integrity": "sha512-T7jf+5zgsZHwNJ4lvQ7/aezbyk0nNX+zJVWpmHA7VYsEx7a7qr5Rg5IbtJFqkgze5Y2sruq1RUY8Q837Od7iFw==",
      "license": "MIT"
    },
    "node_modules/@types/estree": {
      "version": "1.0.9",
      "resolved": "https://registry.npmjs.org/@types/estree/-/estree-1.0.9.tgz",
      "integrity": "sha512-GhdPgy1el4/ImP05X05Uw4cw2/M93BCUmnEvWZNStlCzEKME4Fkk+YpoA5OiHNQmoS7Cafb8Xa3Pya8m1Qrzeg==",
      "license": "MIT"
    },
    "node_modules/@vitest/mocker": {
      "version": "4.1.10",
      "resolved": "https://registry.npmjs.org/@vitest/mocker/-/mocker-4.1.10.tgz",
      "integrity": "sha512-v0xaezt+DKEmKfaxg133ldzADrwLGd7Ze1MfQQTYfvs8OqZIwbxyxaYURivwV7sWy5fqn3rH5uOrSp07bp44Ow==",
      "license": "MIT",
      "dependencies": {
        "@vitest/spy": "4.1.10",
        "estree-walker": "^3.0.3",
        "magic-string": "^0.30.21"
      },
      "funding": {
        "url": "https://opencollective.com/vitest"
      },
      "peerDependencies": {
        "msw": "^2.4.9",
        "vite": "^6.0.0 || ^7.0.0 || ^8.0.0"
      },
      "peerDependenciesMeta": {
        "msw": {
          "optional": true
        },
        "vite": {
          "optional": true
        }
      }
    },
    "node_modules/@vitest/spy": {
      "version": "4.1.10",
      "resolved": "https://registry.npmjs.org/@vitest/spy/-/spy-4.1.10.tgz",
      "integrity": "sha512-PLf/Ugvoq5wO/b4rwYCR1h2PSIdXz7wnkQFMiUpLdtM7l6pqVFcQIBEHyT1+l+cj7mNwAfZHzqXqDyjvOuwbDw==",
      "license": "MIT",
      "funding": {
        "url": "https://opencollective.com/vitest"
      }
    },
    "node_modules/estree-walker": {
      "version": "3.0.3",
      "resolved": "https://registry.npmjs.org/estree-walker/-/estree-walker-3.0.3.tgz",
      "integrity": "sha512-7RUKfXgSMMkzt6ZuXmqapOurLGPPfgj6l9uRZ7lRGolvk0y2yocc35LdcxKC5PQZdn2DMqioAQ2NoWcrTKmm6g==",
      "license": "MIT",
      "dependencies": {
        "@types/estree": "^1.0.0"
      }
    },
    "node_modules/magic-string": {
      "version": "0.30.21",
      "resolved": "https://registry.npmjs.org/magic-string/-/magic-string-0.30.21.tgz",
      "integrity": "sha512-vd2F4YUyEXKGcLHoq+TEyCjxueSeHnFxyyjNp80yg0XV4vUhnDer/lvvlqM/arB5bXQN5K2/3oinyCRyx8T2CQ==",
      "license": "MIT",
      "dependencies": {
        "@jridgewell/sourcemap-codec": "^1.5.5"
      }
    }
  }
}

{
  "name": "sample-vitest-mocker-find-mock-redirect",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "@vitest/mocker": "4.1.10"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify @vitest/mocker.findMockRedirect in pkg:npm/%40vitest/mocker@4.1.10",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40vitest/mocker@4.1.10"
  ],
  "symbols": [
    "@vitest/mocker.findMockRedirect"
  ]
}

import { findMockRedirect } from "@vitest/mocker/redirect";

export function resolveMockRedirect(root, mockPath, external = null) {
  return findMockRedirect(root, mockPath, external);
}

export function resolveExternalMock(root, moduleName) {
  return findMockRedirect(root, moduleName, moduleName);
}

export function resolveBuiltinMock(root, builtinName) {
  return findMockRedirect(root, builtinName, null);
}

export function resolveLocalMock(root, filePath) {
  return findMockRedirect(root, filePath, null);
}

export { findMockRedirect };

import assert from "node:assert/strict";
import fs from "node:fs";
import path from "node:path";
import os from "node:os";
import {
  findMockRedirect,
  resolveMockRedirect,
  resolveExternalMock,
  resolveBuiltinMock,
  resolveLocalMock
} from "../src/index.mjs";

const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "vitest-find-mock-test-"));
const projectRoot = path.join(tempDir, "sample-project");

try {
  // Set up mock directory structures
  const rootMocks = path.join(projectRoot, "__mocks__");
  fs.mkdirSync(rootMocks, { recursive: true });

  // 1. Single-file external mock: <root>/__mocks__/lodash.js
  const lodashMockPath = path.join(rootMocks, "lodash.js");
  fs.writeFileSync(lodashMockPath, "export default { debounce: () => {} };");

  // 2. Directory-based external mock with index: <root>/__mocks__/axios/index.js
  const axiosMockDir = path.join(rootMocks, "axios");
  fs.mkdirSync(axiosMockDir, { recursive: true });
  const axiosMockPath = path.join(axiosMockDir, "index.js");
  fs.writeFileSync(axiosMockPath, "export default { get: async () => ({ data: {} }) };");

  // 3. Node built-in mock: <root>/__mocks__/fs.js
  const fsMockPath = path.join(rootMocks, "fs.js");
  fs.writeFileSync(fsMockPath, "export default { readFileSync: () => '' };");

  // 4. Local source file and its adjacent __mocks__ file:
  //    <root>/src/utils/math.js and <root>/src/utils/__mocks__/math.js
  const utilsDir = path.join(projectRoot, "src", "utils");
  const localMocksDir = path.join(utilsDir, "__mocks__");
  fs.mkdirSync(localMocksDir, { recursive: true });

  const localFilePath = path.join(utilsDir, "math.js");
  const localMockPath = path.join(localMocksDir, "math.js");
  fs.writeFileSync(localFilePath, "export function add(a, b) { return a + b; }");
  fs.writeFileSync(localMockPath, "export function add(a, b) { return 0; }");

  // Test 1: findMockRedirect resolves __mocks__ file for external node module specifiers
  {
    const resolved = resolveExternalMock(projectRoot, "lodash");
    assert.equal(typeof resolved, "string");
    assert.equal(path.resolve(resolved), path.resolve(lodashMockPath));

    const direct = findMockRedirect(projectRoot, "lodash", "lodash");
    assert.equal(path.resolve(direct), path.resolve(lodashMockPath));
  }

  // Test 2: findMockRedirect resolves __mocks__/<dir>/index file for directory-based external mocks
  {
    const resolved = resolveExternalMock(projectRoot, "axios");
    assert.equal(typeof resolved, "string");
    assert.equal(path.resolve(resolved), path.resolve(axiosMockPath));

    const direct = findMockRedirect(projectRoot, "axios", "axios");
    assert.equal(path.resolve(direct), path.resolve(axiosMockPath));
  }

  // Test 3: findMockRedirect resolves __mocks__ file for Node.js built-in module specifiers
  {
    const resolved = resolveBuiltinMock(projectRoot, "fs");
    assert.equal(typeof resolved, "string");
    assert.equal(path.resolve(resolved), path.resolve(fsMockPath));

    const direct = findMockRedirect(projectRoot, "fs", null);
    assert.equal(path.resolve(direct), path.resolve(fsMockPath));
  }

  // Test 4: findMockRedirect resolves adjacent __mocks__ file for local file paths
  {
    const resolved = resolveLocalMock(projectRoot, localFilePath);
    assert.equal(typeof resolved, "string");
    assert.equal(path.resolve(resolved), path.resolve(localMockPath));

    const direct = findMockRedirect(projectRoot, localFilePath, null);
    assert.equal(path.resolve(direct), path.resolve(localMockPath));
  }

  // Test 5: findMockRedirect returns null when no mock definition exists in __mocks__ directory
  {
    const unmockedExternal = resolveExternalMock(projectRoot, "nonexistent-library");
    assert.equal(unmockedExternal, null);

    const nonexistentLocal = resolveLocalMock(projectRoot, path.join(utilsDir, "nonexistent.js"));
    assert.equal(nonexistentLocal, null);

    const directNull = findMockRedirect(projectRoot, "missing", "missing");
    assert.equal(directNull, null);
  }

  console.log("All @vitest/mocker.findMockRedirect contract tests passed successfully.");
} finally {
  fs.rmSync(tempDir, { recursive: true, force: true });
}