From 3f33ad80511731f818e76c2bc454f3648764d7e7 Mon Sep 17 00:00:00 2001
From: Sergey Zelenov <sergey.zelenov@mongodb.com>
Date: Tue, 20 Jan 2026 14:56:54 +0100
Subject: [PATCH 01/12] test(NODE-7345): custom vm.Context runner for mocha

---
 test/tools/runner/vm_runner.js | 207 +++++++++++++++++++++++++++++++++
 1 file changed, 207 insertions(+)
 create mode 100644 test/tools/runner/vm_runner.js

diff --git a/test/tools/runner/vm_runner.js b/test/tools/runner/vm_runner.js
new file mode 100644
index 0000000000..9421dc8bcf
--- /dev/null
+++ b/test/tools/runner/vm_runner.js
@@ -0,0 +1,207 @@
+/* eslint-disable no-restricted-globals */
+
+const fs = require('node:fs');
+const path = require('node:path');
+const vm = require('node:vm');
+const ts = require('typescript');
+const Mocha = require('mocha');
+
+require('ts-node/register');
+require('source-map-support/register');
+
+const mocha = new Mocha({
+  extension: ['js', 'ts'],
+  ui: 'test/tools/runner/metadata_ui.js',
+  recursive: true,
+  timeout: 60000,
+  failZero: true,
+  reporter: 'test/tools/reporter/mongodb_reporter.js',
+  sort: true,
+  color: true,
+  ignore: [
+    'test/integration/node-specific/examples/handler.js',
+    'test/integration/node-specific/examples/handler.test.js',
+    'test/integration/node-specific/examples/aws_handler.js',
+    'test/integration/node-specific/examples/aws_handler.test.js',
+    'test/integration/node-specific/examples/setup.js',
+    'test/integration/node-specific/examples/transactions.test.js',
+    'test/integration/node-specific/examples/versioned_api.js'
+  ]
+});
+mocha.suite.emit('pre-require', global, 'host-context', mocha);
+
+require('./throw_rejections.cjs');
+require('./chai_addons.ts');
+require('./ee_checker.ts');
+
+for (const path of ['./hooks/leak_checker.ts', './hooks/configuration.ts']) {
+  const mod = require(path);
+  const hooks = mod.mochaHooks;
+  const register = (hookName, globalFn) => {
+    if (hooks[hookName]) {
+      const list = Array.isArray(hooks[hookName]) ? hooks[hookName] : [hooks[hookName]];
+      list.forEach(fn => globalFn(fn));
+    }
+  };
+
+  register('beforeAll', global.before);
+  register('afterAll', global.after);
+  register('beforeEach', global.beforeEach);
+  register('afterEach', global.afterEach);
+}
+
+let compilerOptions = { module: ts.ModuleKind.CommonJS };
+const tsConfigPath = path.join(__dirname, '../../tsconfig.json');
+const configFile = ts.readConfigFile(tsConfigPath, ts.sys.readFile);
+if (!configFile.error) {
+  const parsedConfig = ts.parseJsonConfigFileContent(
+    configFile.config,
+    ts.sys,
+    path.dirname(tsConfigPath)
+  );
+  compilerOptions = {
+    ...parsedConfig.options,
+    module: ts.ModuleKind.CommonJS,
+    sourceMap: false,
+    inlineSourceMap: false
+  };
+}
+
+const moduleCache = new Map();
+
+function createSandboxContext(filename) {
+  const exportsContainer = {};
+  return {
+    console: console,
+    AbortController: AbortController,
+    AbortSignal: AbortSignal,
+
+    context: global.context,
+    describe: global.describe,
+    xdescribe: global.xdescribe,
+    it: global.it,
+    xit: global.xit,
+    before: global.before,
+    after: global.after,
+    beforeEach: global.beforeEach,
+    afterEach: global.afterEach,
+
+    exports: exportsContainer,
+    module: { exports: exportsContainer },
+    __filename: filename,
+    __dirname: path.dirname(filename),
+
+    // Buffer: Buffer,
+    queueMicrotask: queueMicrotask
+  };
+}
+
+function createProxiedRequire(parentPath) {
+  const parentDir = path.dirname(parentPath);
+
+  return function sandboxRequire(moduleIdentifier) {
+    if (!moduleIdentifier.startsWith('.')) {
+      return require(moduleIdentifier);
+    }
+
+    const absolutePath = path.resolve(parentDir, moduleIdentifier);
+
+    let fullPath;
+    try {
+      fullPath = require.resolve(absolutePath);
+    } catch (e) {
+      if (e.code === 'MODULE_NOT_FOUND') {
+        const alternatives = [absolutePath + '.ts', path.join(absolutePath, 'index.ts')];
+
+        for (const alt of alternatives) {
+          try {
+            fullPath = require.resolve(alt);
+            break;
+          } catch {}
+        }
+
+        if (!fullPath) {
+          return require(moduleIdentifier);
+        }
+      } else {
+        throw e;
+      }
+    }
+
+    if (fullPath.includes('node_modules')) {
+      return require(fullPath);
+    }
+
+    if (fullPath.endsWith('.ts') || fullPath.endsWith('.js')) {
+      return loadInSandbox(fullPath);
+    }
+
+    return require(fullPath);
+  };
+}
+
+function loadInSandbox(filepath) {
+  const realPath = fs.realpathSync(filepath);
+
+  if (moduleCache.has(realPath)) {
+    return moduleCache.get(realPath);
+  }
+
+  const content = fs.readFileSync(realPath, 'utf8');
+
+  const transpiled = ts.transpileModule(content, {
+    compilerOptions: compilerOptions,
+    filename: realPath
+  });
+
+  const sandbox = createSandboxContext(realPath);
+  sandbox.require = createProxiedRequire(realPath);
+
+  moduleCache.set(realPath, sandbox.module.exports);
+
+  try {
+    const script = new vm.Script(transpiled.outputText, { filename: realPath });
+    script.runInNewContext(sandbox);
+  } catch (err) {
+    console.error(`Error running ${realPath} in sandbox:`, err.message);
+    throw err;
+  }
+
+  moduleCache.set(realPath, sandbox.module.exports);
+  return sandbox.module.exports;
+}
+
+// use it similar to regular mocha:
+//   mocha --config test/mocha_mongodb.js test/integration
+//   node test/runner/vm_context.js test/integration
+const userArgs = process.argv.slice(2);
+const searchTargets = userArgs.length > 0 ? userArgs : ['test'];
+const testFiles = searchTargets.flatMap(target => {
+  try {
+    const stats = fs.statSync(target);
+    if (stats.isDirectory()) {
+      const pattern = path.join(target, '**/*.test.{ts,js}').replace(/\\/g, '/');
+      return fs.globSync(pattern);
+    }
+    if (stats.isFile()) {
+      return [target];
+    }
+  } catch {
+    console.error(`Error: Could not find path "${target}"`);
+  }
+  return [];
+});
+
+if (testFiles.length === 0) {
+  console.log('No test files found.');
+  process.exit(0);
+}
+
+testFiles.forEach(file => {
+  loadInSandbox(path.resolve(file));
+});
+
+console.log('Running Tests...');
+mocha.run(failures => {
+  process.exitCode = failures ? 1 : 0;
+});

From e267e34360f17ac19f93efa411ed07d8a7d10e0a Mon Sep 17 00:00:00 2001
From: Sergey Zelenov <sergey.zelenov@mongodb.com>
Date: Fri, 23 Jan 2026 14:07:48 +0100
Subject: [PATCH 02/12] address review comments

---
 .evergreen/config.yml                        |  13 ++
 .evergreen/generate_evergreen_tasks.js       |  15 ++
 .evergreen/run-runtime-independence-tests.sh |  28 +++
 package.json                                 |   1 +
 test/tools/runner/vm_runner.js               | 207 ------------------
 test/tools/runner/vm_runner.ts               | 211 +++++++++++++++++++
 6 files changed, 268 insertions(+), 207 deletions(-)
 create mode 100644 .evergreen/run-runtime-independence-tests.sh
 delete mode 100644 test/tools/runner/vm_runner.js
 create mode 100644 test/tools/runner/vm_runner.ts

diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index e5f5c0962e..5a98c38b1d 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -2021,6 +2021,19 @@ tasks:
       - func: bootstrap mongo-orchestration
       - func: assume secrets manager role
       - func: build and test alpine FLE
+  - name: test-runtime-independence
+    tags: []
+    commands:
+      - command: expansions.update
+        type: setup
+        params:
+          updates:
+            - {key: NODE_LTS_VERSION, value: 20.19.0}
+            - {key: VERSION, value: '7.0'}
+            - {key: TOPOLOGY, value: replica_set}
+      - func: install dependencies
+      - func: bootstrap mongo-orchestration
+      - func: run tests
   - name: test-latest-server-noauth
     tags:
       - latest
diff --git a/.evergreen/generate_evergreen_tasks.js b/.evergreen/generate_evergreen_tasks.js
index ff977cdede..c0b2ceea92 100644
--- a/.evergreen/generate_evergreen_tasks.js
+++ b/.evergreen/generate_evergreen_tasks.js
@@ -649,6 +649,21 @@ SINGLETON_TASKS.push({
   ]
 });
 
+SINGLETON_TASKS.push({
+  name: 'test-runtime-independence',
+  tags: [],
+  commands: [
+    updateExpansions({
+      NODE_LTS_VERSION: LOWEST_LTS,
+      VERSION: '7.0',
+      TOPOLOGY: 'replica_set'
+    }),
+    { func: 'install dependencies' },
+    { func: 'bootstrap mongo-orchestration' },
+    { func: 'run tests' }
+  ]
+});
+
 function addPerformanceTasks() {
   const makePerfTask = (name, MONGODB_CLIENT_OPTIONS) => ({
     name,
diff --git a/.evergreen/run-runtime-independence-tests.sh b/.evergreen/run-runtime-independence-tests.sh
new file mode 100644
index 0000000000..5cfe2fa324
--- /dev/null
+++ b/.evergreen/run-runtime-independence-tests.sh
@@ -0,0 +1,28 @@
+#!/bin/bash
+# set -o xtrace   # Write all commands first to stderr
+set -o errexit # Exit the script with error if any of the commands fail
+
+# Supported/used environment variables:
+#       AUTH                    Set to enable authentication. Defaults to "noauth"
+#       MONGODB_URI             Set the suggested connection MONGODB_URI (including credentials and topology info)
+#       MARCH                   Machine Architecture. Defaults to lowercase uname -m
+#       SKIP_DEPS               Skip installing dependencies
+
+AUTH=${AUTH:-noauth}
+MONGODB_URI=${MONGODB_URI:-}
+SKIP_DEPS=${SKIP_DEPS:-true}
+
+# run tests
+echo "Running $AUTH tests, connecting to $MONGODB_URI"
+
+if [[ -z "${SKIP_DEPS}" ]]; then
+  source "${PROJECT_DIRECTORY}/.evergreen/install-dependencies.sh"
+else
+  source $DRIVERS_TOOLS/.evergreen/init-node-and-npm-env.sh
+fi
+
+export AUTH=$AUTH
+export MONGODB_API_VERSION=${MONGODB_API_VERSION}
+export MONGODB_URI=${MONGODB_URI}
+
+npx nyc npm run check:runtime-independence
diff --git a/package.json b/package.json
index 3f7c7f8366..c584b814ae 100644
--- a/package.json
+++ b/package.json
@@ -157,6 +157,7 @@
     "check:csfle": "nyc mocha --config test/mocha_mongodb.js test/integration/client-side-encryption",
     "check:snappy": "nyc mocha test/unit/assorted/snappy.test.js",
     "check:x509": "nyc mocha test/manual/x509_auth.test.ts",
+    "check:runtime-independence": "ts-node test/tools/runner/vm_runner.ts test/integration/change-streams/change_stream.test.ts",
     "fix:eslint": "npm run check:eslint -- --fix",
     "prepare": "node etc/prepare.js",
     "preview:docs": "ts-node etc/docs/preview.ts",
diff --git a/test/tools/runner/vm_runner.js b/test/tools/runner/vm_runner.js
deleted file mode 100644
index 9421dc8bcf..0000000000
--- a/test/tools/runner/vm_runner.js
+++ /dev/null
@@ -1,207 +0,0 @@
-/* eslint-disable no-restricted-globals */
-
-const fs = require('node:fs');
-const path = require('node:path');
-const vm = require('node:vm');
-const ts = require('typescript');
-const Mocha = require('mocha');
-
-require('ts-node/register');
-require('source-map-support/register');
-
-const mocha = new Mocha({
-  extension: ['js', 'ts'],
-  ui: 'test/tools/runner/metadata_ui.js',
-  recursive: true,
-  timeout: 60000,
-  failZero: true,
-  reporter: 'test/tools/reporter/mongodb_reporter.js',
-  sort: true,
-  color: true,
-  ignore: [
-    'test/integration/node-specific/examples/handler.js',
-    'test/integration/node-specific/examples/handler.test.js',
-    'test/integration/node-specific/examples/aws_handler.js',
-    'test/integration/node-specific/examples/aws_handler.test.js',
-    'test/integration/node-specific/examples/setup.js',
-    'test/integration/node-specific/examples/transactions.test.js',
-    'test/integration/node-specific/examples/versioned_api.js'
-  ]
-});
-mocha.suite.emit('pre-require', global, 'host-context', mocha);
-
-require('./throw_rejections.cjs');
-require('./chai_addons.ts');
-require('./ee_checker.ts');
-
-for (const path of ['./hooks/leak_checker.ts', './hooks/configuration.ts']) {
-  const mod = require(path);
-  const hooks = mod.mochaHooks;
-  const register = (hookName, globalFn) => {
-    if (hooks[hookName]) {
-      const list = Array.isArray(hooks[hookName]) ? hooks[hookName] : [hooks[hookName]];
-      list.forEach(fn => globalFn(fn));
-    }
-  };
-
-  register('beforeAll', global.before);
-  register('afterAll', global.after);
-  register('beforeEach', global.beforeEach);
-  register('afterEach', global.afterEach);
-}
-
-let compilerOptions = { module: ts.ModuleKind.CommonJS };
-const tsConfigPath = path.join(__dirname, '../../tsconfig.json');
-const configFile = ts.readConfigFile(tsConfigPath, ts.sys.readFile);
-if (!configFile.error) {
-  const parsedConfig = ts.parseJsonConfigFileContent(
-    configFile.config,
-    ts.sys,
-    path.dirname(tsConfigPath)
-  );
-  compilerOptions = {
-    ...parsedConfig.options,
-    module: ts.ModuleKind.CommonJS,
-    sourceMap: false,
-    inlineSourceMap: false
-  };
-}
-
-const moduleCache = new Map();
-
-function createSandboxContext(filename) {
-  const exportsContainer = {};
-  return {
-    console: console,
-    AbortController: AbortController,
-    AbortSignal: AbortSignal,
-
-    context: global.context,
-    describe: global.describe,
-    xdescribe: global.xdescribe,
-    it: global.it,
-    xit: global.xit,
-    before: global.before,
-    after: global.after,
-    beforeEach: global.beforeEach,
-    afterEach: global.afterEach,
-
-    exports: exportsContainer,
-    module: { exports: exportsContainer },
-    __filename: filename,
-    __dirname: path.dirname(filename),
-
-    // Buffer: Buffer,
-    queueMicrotask: queueMicrotask
-  };
-}
-
-function createProxiedRequire(parentPath) {
-  const parentDir = path.dirname(parentPath);
-
-  return function sandboxRequire(moduleIdentifier) {
-    if (!moduleIdentifier.startsWith('.')) {
-      return require(moduleIdentifier);
-    }
-
-    const absolutePath = path.resolve(parentDir, moduleIdentifier);
-
-    let fullPath;
-    try {
-      fullPath = require.resolve(absolutePath);
-    } catch (e) {
-      if (e.code === 'MODULE_NOT_FOUND') {
-        const alternatives = [absolutePath + '.ts', path.join(absolutePath, 'index.ts')];
-
-        for (const alt of alternatives) {
-          try {
-            fullPath = require.resolve(alt);
-            break;
-          } catch {}
-        }
-
-        if (!fullPath) {
-          return require(moduleIdentifier);
-        }
-      } else {
-        throw e;
-      }
-    }
-
-    if (fullPath.includes('node_modules')) {
-      return require(fullPath);
-    }
-
-    if (fullPath.endsWith('.ts') || fullPath.endsWith('.js')) {
-      return loadInSandbox(fullPath);
-    }
-
-    return require(fullPath);
-  };
-}
-
-function loadInSandbox(filepath) {
-  const realPath = fs.realpathSync(filepath);
-
-  if (moduleCache.has(realPath)) {
-    return moduleCache.get(realPath);
-  }
-
-  const content = fs.readFileSync(realPath, 'utf8');
-
-  const transpiled = ts.transpileModule(content, {
-    compilerOptions: compilerOptions,
-    filename: realPath
-  });
-
-  const sandbox = createSandboxContext(realPath);
-  sandbox.require = createProxiedRequire(realPath);
-
-  moduleCache.set(realPath, sandbox.module.exports);
-
-  try {
-    const script = new vm.Script(transpiled.outputText, { filename: realPath });
-    script.runInNewContext(sandbox);
-  } catch (err) {
-    console.error(`Error running ${realPath} in sandbox:`, err.message);
-    throw err;
-  }
-
-  moduleCache.set(realPath, sandbox.module.exports);
-  return sandbox.module.exports;
-}
-
-// use it similar to regular mocha:
-//   mocha --config test/mocha_mongodb.js test/integration
-//   node test/runner/vm_context.js test/integration
-const userArgs = process.argv.slice(2);
-const searchTargets = userArgs.length > 0 ? userArgs : ['test'];
-const testFiles = searchTargets.flatMap(target => {
-  try {
-    const stats = fs.statSync(target);
-    if (stats.isDirectory()) {
-      const pattern = path.join(target, '**/*.test.{ts,js}').replace(/\\/g, '/');
-      return fs.globSync(pattern);
-    }
-    if (stats.isFile()) {
-      return [target];
-    }
-  } catch {
-    console.error(`Error: Could not find path "${target}"`);
-  }
-  return [];
-});
-
-if (testFiles.length === 0) {
-  console.log('No test files found.');
-  process.exit(0);
-}
-
-testFiles.forEach(file => {
-  loadInSandbox(path.resolve(file));
-});
-
-console.log('Running Tests...');
-mocha.run(failures => {
-  process.exitCode = failures ? 1 : 0;
-});
diff --git a/test/tools/runner/vm_runner.ts b/test/tools/runner/vm_runner.ts
new file mode 100644
index 0000000000..4ff9e2fc09
--- /dev/null
+++ b/test/tools/runner/vm_runner.ts
@@ -0,0 +1,211 @@
+/* eslint-disable no-restricted-globals, @typescript-eslint/no-require-imports */
+
+import * as fs from 'node:fs';
+import { isBuiltin } from 'node:module';
+import * as path from 'node:path';
+import * as vm from 'node:vm';
+
+import * as Mocha from 'mocha';
+import * as ts from 'typescript';
+
+import * as mochaConfiguration from '../../mocha_mongodb';
+
+const mocha = new Mocha(mochaConfiguration);
+mocha.suite.emit('pre-require', global, 'host-context', mocha);
+
+// mocha hooks and custom "require" modules needs to be loaded and injected separately
+require('./throw_rejections.cjs');
+require('./chai_addons.ts');
+require('./ee_checker.ts');
+for (const path of ['./hooks/leak_checker.ts', './hooks/configuration.ts']) {
+  const mod = require(path);
+  const hooks = mod.mochaHooks;
+  const register = (hookName, globalFn) => {
+    if (hooks[hookName]) {
+      const list = Array.isArray(hooks[hookName]) ? hooks[hookName] : [hooks[hookName]];
+      list.forEach(fn => globalFn(fn));
+    }
+  };
+
+  register('beforeAll', global.before);
+  register('afterAll', global.after);
+  register('beforeEach', global.beforeEach);
+  register('afterEach', global.afterEach);
+}
+
+let compilerOptions: ts.CompilerOptions = { module: ts.ModuleKind.CommonJS };
+const tsConfigPath = path.join(__dirname, '../../tsconfig.json');
+const configFile = ts.readConfigFile(tsConfigPath, ts.sys.readFile);
+if (!configFile.error) {
+  const parsedConfig = ts.parseJsonConfigFileContent(
+    configFile.config,
+    ts.sys,
+    path.dirname(tsConfigPath)
+  );
+  compilerOptions = {
+    ...parsedConfig.options,
+    module: ts.ModuleKind.CommonJS,
+    sourceMap: false,
+    // inline source map for stack traces
+    inlineSourceMap: true
+  };
+}
+
+const moduleCache = new Map();
+
+const sandbox = vm.createContext({
+  __proto__: null,
+
+  console: console,
+  AbortController: AbortController,
+  AbortSignal: AbortSignal,
+  Date: global.Date,
+  Error: global.Error,
+  URL: global.URL,
+  URLSearchParams: global.URLSearchParams,
+  queueMicrotask: queueMicrotask,
+
+  process: process,
+  Buffer: Buffer,
+
+  context: global.context,
+  describe: global.describe,
+  xdescribe: global.xdescribe,
+  it: global.it,
+  xit: global.xit,
+  before: global.before,
+  after: global.after,
+  beforeEach: global.beforeEach,
+  afterEach: global.afterEach
+});
+
+function createProxiedRequire(parentPath: string) {
+  const parentDir = path.dirname(parentPath);
+
+  return function sandboxRequire(moduleIdentifier: string) {
+    // allow all code modules be imported by the host environment
+    if (isBuiltin(moduleIdentifier)) {
+      return require(moduleIdentifier);
+    }
+
+    // list of dependencies we want to import from within the sandbox
+    const sandboxedDependencies = ['bson'];
+    const isSandboxedDep = sandboxedDependencies.some(
+      dep => moduleIdentifier === dep || moduleIdentifier.startsWith(`${dep}/`)
+    );
+    if (!moduleIdentifier.startsWith('.') && !isSandboxedDep) {
+      return require(moduleIdentifier);
+    }
+
+    // require.resolve throws if module can't be loaded, let it bubble up
+    const fullPath = require.resolve(moduleIdentifier, { paths: [parentDir] });
+    return loadInSandbox(fullPath);
+  };
+}
+
+function loadInSandbox(filepath: string) {
+  const realPath = fs.realpathSync(filepath);
+
+  if (moduleCache.has(realPath)) {
+    return moduleCache.get(realPath);
+  }
+
+  // clientmetadata requires package.json to fetch driver's version
+  if (realPath.endsWith('.json')) {
+    const jsonContent = JSON.parse(fs.readFileSync(realPath, 'utf8'));
+    moduleCache.set(realPath, jsonContent);
+    return jsonContent;
+  }
+
+  const content = fs.readFileSync(realPath, 'utf8');
+  let executableCode: string;
+  if (realPath.endsWith('.ts')) {
+    executableCode = ts.transpileModule(content, {
+      compilerOptions: compilerOptions,
+      fileName: realPath
+    }).outputText;
+  } else {
+    // .js or .cjs should work just fine
+    executableCode = content;
+  }
+
+  const exportsContainer = {};
+  const localModule = { exports: exportsContainer };
+  const localRequire = createProxiedRequire(realPath);
+  const filename = realPath;
+  const dirname = path.dirname(realPath);
+
+  // prevent recursion
+  moduleCache.set(realPath, localModule.exports);
+
+  try {
+    const wrapper = `(function(exports, require, module, __filename, __dirname) {
+      ${executableCode}
+    })`;
+    const script = new vm.Script(wrapper, { filename: realPath });
+    const fn = script.runInContext(sandbox);
+
+    fn(localModule.exports, localRequire, localModule, filename, dirname);
+
+    const result = localModule.exports;
+    if (realPath.includes('src/error.ts')) {
+      for (const [key, value] of Object.entries(result)) {
+        if (typeof value === 'function' && value.name?.startsWith('Mongo')) {
+          (sandbox as any)[key] = value;
+
+          // force instanceof to work across contexts by defining custom `instanceof` function
+          Object.defineProperty(value, Symbol.hasInstance, {
+            value: (instance: any) => {
+              return (
+                instance && (instance.constructor.name === value.name || instance instanceof value)
+              );
+            }
+          });
+        }
+      }
+    }
+
+    moduleCache.set(realPath, result);
+
+    return result;
+  } catch (err: any) {
+    moduleCache.delete(realPath);
+    console.error(`Error running ${realPath} in sandbox:`, err.stack);
+    throw err;
+  }
+}
+
+// use it similar to regular mocha:
+//   mocha --config test/mocha_mongodb.js test/integration
+//   ts-node test/runner/vm_context.ts test/integration
+const userArgs = process.argv.slice(2);
+const searchTargets = userArgs.length > 0 ? userArgs : ['test'];
+const testFiles = searchTargets.flatMap(target => {
+  try {
+    const stats = fs.statSync(target);
+    if (stats.isDirectory()) {
+      const pattern = path.join(target, '**/*.test.{ts,js}').replace(/\\/g, '/');
+      return fs.globSync(pattern);
+    }
+    if (stats.isFile()) {
+      return [target];
+    }
+  } catch {
+    console.error(`Error: Could not find path "${target}"`);
+  }
+  return [];
+});
+
+if (testFiles.length === 0) {
+  console.log('No test files found.');
+  process.exit(0);
+}
+
+testFiles.forEach(file => {
+  loadInSandbox(path.resolve(file));
+});
+
+console.log('Running Tests...');
+mocha.run(failures => {
+  process.exitCode = failures ? 1 : 0;
+});

From 8f98008e147008286a76aff3e6ee0d8ac9ebbcab Mon Sep 17 00:00:00 2001
From: Sergey Zelenov <sergey.zelenov@mongodb.com>
Date: Fri, 23 Jan 2026 14:16:16 +0100
Subject: [PATCH 03/12] throw if ts config is missing

---
 test/tools/runner/vm_runner.ts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/test/tools/runner/vm_runner.ts b/test/tools/runner/vm_runner.ts
index 4ff9e2fc09..52c276ffe6 100644
--- a/test/tools/runner/vm_runner.ts
+++ b/test/tools/runner/vm_runner.ts
@@ -49,6 +49,8 @@ if (!configFile.error) {
     // inline source map for stack traces
     inlineSourceMap: true
   };
+} else {
+  throw new Error('tsconfig is missing');
 }
 
 const moduleCache = new Map();

From a7b383a3e75b8a98ba37ddd997363406f4845b06 Mon Sep 17 00:00:00 2001
From: Sergey Zelenov <sergey.zelenov@mongodb.com>
Date: Fri, 23 Jan 2026 14:23:10 +0100
Subject: [PATCH 04/12] run tests on evegreen

---
 .evergreen/config.yml                  | 9 +++++----
 .evergreen/generate_evergreen_tasks.js | 8 ++++----
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index 5a98c38b1d..150119cd55 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -2022,18 +2022,19 @@ tasks:
       - func: assume secrets manager role
       - func: build and test alpine FLE
   - name: test-runtime-independence
-    tags: []
+    tags:
+      - runtime-independency-tests
     commands:
       - command: expansions.update
         type: setup
         params:
           updates:
-            - {key: NODE_LTS_VERSION, value: 20.19.0}
-            - {key: VERSION, value: '7.0'}
+            - {key: NODE_LTS_VERSION, value: '24'}
+            - {key: VERSION, value: latest}
             - {key: TOPOLOGY, value: replica_set}
       - func: install dependencies
       - func: bootstrap mongo-orchestration
-      - func: run tests
+      - func: run runtime independence tests
   - name: test-latest-server-noauth
     tags:
       - latest
diff --git a/.evergreen/generate_evergreen_tasks.js b/.evergreen/generate_evergreen_tasks.js
index c0b2ceea92..47650b8ef2 100644
--- a/.evergreen/generate_evergreen_tasks.js
+++ b/.evergreen/generate_evergreen_tasks.js
@@ -651,16 +651,16 @@ SINGLETON_TASKS.push({
 
 SINGLETON_TASKS.push({
   name: 'test-runtime-independence',
-  tags: [],
+  tags: ['runtime-independency-tests'],
   commands: [
     updateExpansions({
-      NODE_LTS_VERSION: LOWEST_LTS,
-      VERSION: '7.0',
+      NODE_LTS_VERSION: LATEST_LTS,
+      VERSION: 'latest',
       TOPOLOGY: 'replica_set'
     }),
     { func: 'install dependencies' },
     { func: 'bootstrap mongo-orchestration' },
-    { func: 'run tests' }
+    { func: 'run runtime independence tests' }
   ]
 });
 

From 38ff5981ec7ed31ac2e7075ada15a8da8cb7259e Mon Sep 17 00:00:00 2001
From: Sergey Zelenov <sergey.zelenov@mongodb.com>
Date: Fri, 23 Jan 2026 14:40:09 +0100
Subject: [PATCH 05/12] make names consistent

---
 .evergreen/config.yml                                         | 4 ++--
 .evergreen/generate_evergreen_tasks.js                        | 4 ++--
 ...ndependence-tests.sh => run-runtime-independency-tests.sh} | 2 +-
 package.json                                                  | 2 +-
 4 files changed, 6 insertions(+), 6 deletions(-)
 rename .evergreen/{run-runtime-independence-tests.sh => run-runtime-independency-tests.sh} (95%)

diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index 150119cd55..82c906e00a 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -2021,7 +2021,7 @@ tasks:
       - func: bootstrap mongo-orchestration
       - func: assume secrets manager role
       - func: build and test alpine FLE
-  - name: test-runtime-independence
+  - name: test-runtime-independency
     tags:
       - runtime-independency-tests
     commands:
@@ -2034,7 +2034,7 @@ tasks:
             - {key: TOPOLOGY, value: replica_set}
       - func: install dependencies
       - func: bootstrap mongo-orchestration
-      - func: run runtime independence tests
+      - func: run runtime independency tests
   - name: test-latest-server-noauth
     tags:
       - latest
diff --git a/.evergreen/generate_evergreen_tasks.js b/.evergreen/generate_evergreen_tasks.js
index 47650b8ef2..d58dd90552 100644
--- a/.evergreen/generate_evergreen_tasks.js
+++ b/.evergreen/generate_evergreen_tasks.js
@@ -650,7 +650,7 @@ SINGLETON_TASKS.push({
 });
 
 SINGLETON_TASKS.push({
-  name: 'test-runtime-independence',
+  name: 'test-runtime-independency',
   tags: ['runtime-independency-tests'],
   commands: [
     updateExpansions({
@@ -660,7 +660,7 @@ SINGLETON_TASKS.push({
     }),
     { func: 'install dependencies' },
     { func: 'bootstrap mongo-orchestration' },
-    { func: 'run runtime independence tests' }
+    { func: 'run runtime independency tests' }
   ]
 });
 
diff --git a/.evergreen/run-runtime-independence-tests.sh b/.evergreen/run-runtime-independency-tests.sh
similarity index 95%
rename from .evergreen/run-runtime-independence-tests.sh
rename to .evergreen/run-runtime-independency-tests.sh
index 5cfe2fa324..7301925188 100644
--- a/.evergreen/run-runtime-independence-tests.sh
+++ b/.evergreen/run-runtime-independency-tests.sh
@@ -25,4 +25,4 @@ export AUTH=$AUTH
 export MONGODB_API_VERSION=${MONGODB_API_VERSION}
 export MONGODB_URI=${MONGODB_URI}
 
-npx nyc npm run check:runtime-independence
+npm run check:runtime-independency
diff --git a/package.json b/package.json
index c584b814ae..04cd99c653 100644
--- a/package.json
+++ b/package.json
@@ -157,7 +157,7 @@
     "check:csfle": "nyc mocha --config test/mocha_mongodb.js test/integration/client-side-encryption",
     "check:snappy": "nyc mocha test/unit/assorted/snappy.test.js",
     "check:x509": "nyc mocha test/manual/x509_auth.test.ts",
-    "check:runtime-independence": "ts-node test/tools/runner/vm_runner.ts test/integration/change-streams/change_stream.test.ts",
+    "check:runtime-independency": "ts-node test/tools/runner/vm_runner.ts test/integration/change-streams/change_stream.test.ts",
     "fix:eslint": "npm run check:eslint -- --fix",
     "prepare": "node etc/prepare.js",
     "preview:docs": "ts-node etc/docs/preview.ts",

From 626e2a593eb5eedc215a0ca061b6f76ebc96d14b Mon Sep 17 00:00:00 2001
From: Sergey Zelenov <sergey.zelenov@mongodb.com>
Date: Fri, 23 Jan 2026 15:42:35 +0100
Subject: [PATCH 06/12] add test runner in evergreen

---
 .evergreen/config.in.yml       | 12 ++++++++++++
 .evergreen/config.yml          | 13 +++++++++++++
 test/tools/runner/vm_runner.ts |  1 +
 3 files changed, 26 insertions(+)

diff --git a/.evergreen/config.in.yml b/.evergreen/config.in.yml
index 2b5fa1eada..dad0e8326f 100644
--- a/.evergreen/config.in.yml
+++ b/.evergreen/config.in.yml
@@ -113,6 +113,18 @@ functions:
         args:
           - .evergreen/run-tests.sh
 
+  "run runtime independency tests":
+    - <<: *assume_secrets_manager_role
+    - command: subprocess.exec
+      type: test
+      params:
+        add_expansions_to_env: true
+        working_dir: "src"
+        timeout_secs: 300
+        binary: bash
+        args:
+          - .evergreen/run-runtime-independency-tests.sh
+
   "perf send":
     - command: s3.put
       params:
diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index 82c906e00a..c15b2e760c 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -88,6 +88,19 @@ functions:
         binary: bash
         args:
           - .evergreen/run-tests.sh
+  run runtime independency tests:
+    - command: ec2.assume_role
+      params:
+        role_arn: ${DRIVERS_SECRETS_ARN}
+    - command: subprocess.exec
+      type: test
+      params:
+        add_expansions_to_env: true
+        working_dir: src
+        timeout_secs: 300
+        binary: bash
+        args:
+          - .evergreen/run-runtime-independency-tests.sh
   perf send:
     - command: s3.put
       params:
diff --git a/test/tools/runner/vm_runner.ts b/test/tools/runner/vm_runner.ts
index 52c276ffe6..0bdcd1e56c 100644
--- a/test/tools/runner/vm_runner.ts
+++ b/test/tools/runner/vm_runner.ts
@@ -66,6 +66,7 @@ const sandbox = vm.createContext({
   URL: global.URL,
   URLSearchParams: global.URLSearchParams,
   queueMicrotask: queueMicrotask,
+  performance: global.performance,
 
   process: process,
   Buffer: Buffer,

From 1c0af0cbf112f4db66991ef4bab42d49780336cc Mon Sep 17 00:00:00 2001
From: Sergey Zelenov <sergey.zelenov@mongodb.com>
Date: Fri, 23 Jan 2026 18:37:26 +0100
Subject: [PATCH 07/12] add buildvariant to run tests

---
 .evergreen/config.in.yml                          |  9 +++++++--
 .evergreen/config.yml                             | 15 ++++++++++-----
 .evergreen/generate_evergreen_tasks.js            |  6 +++---
 ...tests.sh => run-runtime-independence-tests.sh} |  2 +-
 package.json                                      |  2 +-
 5 files changed, 22 insertions(+), 12 deletions(-)
 rename .evergreen/{run-runtime-independency-tests.sh => run-runtime-independence-tests.sh} (96%)

diff --git a/.evergreen/config.in.yml b/.evergreen/config.in.yml
index dad0e8326f..2eb4a215ff 100644
--- a/.evergreen/config.in.yml
+++ b/.evergreen/config.in.yml
@@ -113,7 +113,7 @@ functions:
         args:
           - .evergreen/run-tests.sh
 
-  "run runtime independency tests":
+  "run runtime independence tests":
     - <<: *assume_secrets_manager_role
     - command: subprocess.exec
       type: test
@@ -123,7 +123,7 @@ functions:
         timeout_secs: 300
         binary: bash
         args:
-          - .evergreen/run-runtime-independency-tests.sh
+          - .evergreen/run-runtime-independence-tests.sh
 
   "perf send":
     - command: s3.put
@@ -1249,3 +1249,8 @@ buildvariants:
     run_on: ubuntu2204-small
     tasks:
       - .alpine-fle
+  - name: Runtime Independence Test
+    display_name: Runtime Independence Test
+    run_on: ubuntu2204-small
+    tasks:
+      - .alpine-fle
diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index c15b2e760c..758f90fd3d 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -88,7 +88,7 @@ functions:
         binary: bash
         args:
           - .evergreen/run-tests.sh
-  run runtime independency tests:
+  run runtime independence tests:
     - command: ec2.assume_role
       params:
         role_arn: ${DRIVERS_SECRETS_ARN}
@@ -100,7 +100,7 @@ functions:
         timeout_secs: 300
         binary: bash
         args:
-          - .evergreen/run-runtime-independency-tests.sh
+          - .evergreen/run-runtime-independence-tests.sh
   perf send:
     - command: s3.put
       params:
@@ -2034,9 +2034,9 @@ tasks:
       - func: bootstrap mongo-orchestration
       - func: assume secrets manager role
       - func: build and test alpine FLE
-  - name: test-runtime-independency
+  - name: test-runtime-independence
     tags:
-      - runtime-independency-tests
+      - runtime-independence-tests
     commands:
       - command: expansions.update
         type: setup
@@ -2047,7 +2047,7 @@ tasks:
             - {key: TOPOLOGY, value: replica_set}
       - func: install dependencies
       - func: bootstrap mongo-orchestration
-      - func: run runtime independency tests
+      - func: run runtime independence tests
   - name: test-latest-server-noauth
     tags:
       - latest
@@ -2885,6 +2885,11 @@ buildvariants:
     run_on: ubuntu2204-small
     tasks:
       - .alpine-fle
+  - name: Runtime Independence Test
+    display_name: Runtime Independence Test
+    run_on: ubuntu2204-small
+    tasks:
+      - .alpine-fle
   - name: rhel80-large-iron
     display_name: rhel8 Node20.19.0
     run_on: rhel80-large
diff --git a/.evergreen/generate_evergreen_tasks.js b/.evergreen/generate_evergreen_tasks.js
index d58dd90552..fdd1dd9bd9 100644
--- a/.evergreen/generate_evergreen_tasks.js
+++ b/.evergreen/generate_evergreen_tasks.js
@@ -650,8 +650,8 @@ SINGLETON_TASKS.push({
 });
 
 SINGLETON_TASKS.push({
-  name: 'test-runtime-independency',
-  tags: ['runtime-independency-tests'],
+  name: 'test-runtime-independence',
+  tags: ['runtime-independence-tests'],
   commands: [
     updateExpansions({
       NODE_LTS_VERSION: LATEST_LTS,
@@ -660,7 +660,7 @@ SINGLETON_TASKS.push({
     }),
     { func: 'install dependencies' },
     { func: 'bootstrap mongo-orchestration' },
-    { func: 'run runtime independency tests' }
+    { func: 'run runtime independence tests' }
   ]
 });
 
diff --git a/.evergreen/run-runtime-independency-tests.sh b/.evergreen/run-runtime-independence-tests.sh
similarity index 96%
rename from .evergreen/run-runtime-independency-tests.sh
rename to .evergreen/run-runtime-independence-tests.sh
index 7301925188..ff75aec814 100644
--- a/.evergreen/run-runtime-independency-tests.sh
+++ b/.evergreen/run-runtime-independence-tests.sh
@@ -25,4 +25,4 @@ export AUTH=$AUTH
 export MONGODB_API_VERSION=${MONGODB_API_VERSION}
 export MONGODB_URI=${MONGODB_URI}
 
-npm run check:runtime-independency
+npm run check:runtime-independence
diff --git a/package.json b/package.json
index 7c33325a54..8a8d7b38af 100644
--- a/package.json
+++ b/package.json
@@ -154,7 +154,7 @@
     "check:csfle": "nyc mocha --config test/mocha_mongodb.js test/integration/client-side-encryption",
     "check:snappy": "nyc mocha test/unit/assorted/snappy.test.js",
     "check:x509": "nyc mocha test/manual/x509_auth.test.ts",
-    "check:runtime-independency": "ts-node test/tools/runner/vm_runner.ts test/integration/change-streams/change_stream.test.ts",
+    "check:runtime-independence": "ts-node test/tools/runner/vm_runner.ts test/integration/change-streams/change_stream.test.ts",
     "fix:eslint": "npm run check:eslint -- --fix",
     "prepare": "node etc/prepare.js",
     "preview:docs": "ts-node etc/docs/preview.ts",

From b5d497ed8125795ca32adefc7ec01164a3334270 Mon Sep 17 00:00:00 2001
From: Sergey Zelenov <sergey.zelenov@mongodb.com>
Date: Fri, 23 Jan 2026 19:31:46 +0100
Subject: [PATCH 08/12] run runtime independence tests

---
 .evergreen/config.in.yml               | 2 +-
 .evergreen/config.yml                  | 4 ++--
 .evergreen/generate_evergreen_tasks.js | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/.evergreen/config.in.yml b/.evergreen/config.in.yml
index 2eb4a215ff..cb327275fb 100644
--- a/.evergreen/config.in.yml
+++ b/.evergreen/config.in.yml
@@ -1253,4 +1253,4 @@ buildvariants:
     display_name: Runtime Independence Test
     run_on: ubuntu2204-small
     tasks:
-      - .alpine-fle
+      - .runtime-independence
diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index 758f90fd3d..f8cb5a6324 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -2036,7 +2036,7 @@ tasks:
       - func: build and test alpine FLE
   - name: test-runtime-independence
     tags:
-      - runtime-independence-tests
+      - runtime-independence
     commands:
       - command: expansions.update
         type: setup
@@ -2889,7 +2889,7 @@ buildvariants:
     display_name: Runtime Independence Test
     run_on: ubuntu2204-small
     tasks:
-      - .alpine-fle
+      - .runtime-independence
   - name: rhel80-large-iron
     display_name: rhel8 Node20.19.0
     run_on: rhel80-large
diff --git a/.evergreen/generate_evergreen_tasks.js b/.evergreen/generate_evergreen_tasks.js
index fdd1dd9bd9..b812611d1b 100644
--- a/.evergreen/generate_evergreen_tasks.js
+++ b/.evergreen/generate_evergreen_tasks.js
@@ -651,7 +651,7 @@ SINGLETON_TASKS.push({
 
 SINGLETON_TASKS.push({
   name: 'test-runtime-independence',
-  tags: ['runtime-independence-tests'],
+  tags: ['runtime-independence'],
   commands: [
     updateExpansions({
       NODE_LTS_VERSION: LATEST_LTS,

From 72896ada924f45829564666dc89b0fd36eccd7d8 Mon Sep 17 00:00:00 2001
From: Sergey Zelenov <sergey.zelenov@mongodb.com>
Date: Mon, 26 Jan 2026 12:27:39 +0100
Subject: [PATCH 09/12] differentiate between src and test files, propagate
 bson Long

---
 .../change-streams/change_stream.test.ts      |  2 +-
 test/tools/runner/vm_runner.ts                | 48 +++++++++++++------
 2 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/test/integration/change-streams/change_stream.test.ts b/test/integration/change-streams/change_stream.test.ts
index a7b8dec85c..ce6dd80eb5 100644
--- a/test/integration/change-streams/change_stream.test.ts
+++ b/test/integration/change-streams/change_stream.test.ts
@@ -1717,7 +1717,7 @@ describe('Change Streams', function () {
         });
       });
 
-      context('when set to false', () => {
+      context.only('when set to false', () => {
         it('converts Long values to native numbers', {
           metadata: { requires: { topology: '!single' } },
           test: async function () {
diff --git a/test/tools/runner/vm_runner.ts b/test/tools/runner/vm_runner.ts
index 0bdcd1e56c..2e1a26a5ee 100644
--- a/test/tools/runner/vm_runner.ts
+++ b/test/tools/runner/vm_runner.ts
@@ -69,7 +69,6 @@ const sandbox = vm.createContext({
   performance: global.performance,
 
   process: process,
-  Buffer: Buffer,
 
   context: global.context,
   describe: global.describe,
@@ -114,12 +113,32 @@ function loadInSandbox(filepath: string) {
   }
 
   // clientmetadata requires package.json to fetch driver's version
-  if (realPath.endsWith('.json')) {
+  if (realPath.endsWith('package.json')) {
     const jsonContent = JSON.parse(fs.readFileSync(realPath, 'utf8'));
     moduleCache.set(realPath, jsonContent);
     return jsonContent;
   }
 
+  // js-bson is allowed to use Buffer, only ./src/ is not
+  const isSourceFile = realPath.includes('/src/') || !realPath.includes('node_modules');
+  const isTestFile = realPath.includes('.test.ts') || realPath.includes('.test.js');
+
+  let localBuffer = Buffer;
+  if (isSourceFile && !isTestFile) {
+    localBuffer = new Proxy(Buffer, {
+      get() {
+        throw new Error(
+          `Forbidden: 'Buffer' usage is not allowed in source files. Use Uint8Array instead. File: ${realPath}`
+        );
+      },
+      construct() {
+        throw new Error(
+          `Forbidden: 'Buffer' usage is not allowed in source files. Use Uint8Array instead. File: ${realPath}`
+        );
+      }
+    }) as any;
+  }
+
   const content = fs.readFileSync(realPath, 'utf8');
   let executableCode: string;
   if (realPath.endsWith('.ts')) {
@@ -142,28 +161,29 @@ function loadInSandbox(filepath: string) {
   moduleCache.set(realPath, localModule.exports);
 
   try {
-    const wrapper = `(function(exports, require, module, __filename, __dirname) {
+    const wrapper = `(function(exports, require, module, __filename, __dirname, Buffer) {
       ${executableCode}
     })`;
     const script = new vm.Script(wrapper, { filename: realPath });
     const fn = script.runInContext(sandbox);
 
-    fn(localModule.exports, localRequire, localModule, filename, dirname);
+    fn(localModule.exports, localRequire, localModule, filename, dirname, localBuffer);
 
     const result = localModule.exports;
-    if (realPath.includes('src/error.ts')) {
-      for (const [key, value] of Object.entries(result)) {
-        if (typeof value === 'function' && value.name?.startsWith('Mongo')) {
-          (sandbox as any)[key] = value;
 
+    const isBSON = realPath.includes('node_modules/bson');
+    const isError = realPath.includes('src/error.ts');
+
+    if (isBSON || isError) {
+      for (const [key, value] of Object.entries(result)) {
+        if (typeof value === 'function' && value.name) {
           // force instanceof to work across contexts by defining custom `instanceof` function
           Object.defineProperty(value, Symbol.hasInstance, {
-            value: (instance: any) => {
-              return (
-                instance && (instance.constructor.name === value.name || instance instanceof value)
-              );
-            }
+            value: (i: any) => i && (i.constructor.name === value.name || i instanceof value)
           });
+
+          // also inject into global for easier access in tests
+          (sandbox as any)[key] = value;
         }
       }
     }
@@ -173,7 +193,7 @@ function loadInSandbox(filepath: string) {
     return result;
   } catch (err: any) {
     moduleCache.delete(realPath);
-    console.error(`Error running ${realPath} in sandbox:`, err.stack);
+    console.error(`Error running ${realPath} in sandbox:`, err);
     throw err;
   }
 }

From 1ea5d927984f5beb327bfa09294514874941c3e0 Mon Sep 17 00:00:00 2001
From: Sergey Zelenov <sergey.zelenov@mongodb.com>
Date: Mon, 26 Jan 2026 13:19:15 +0100
Subject: [PATCH 10/12] allow bson from node_modules to use Buffer

---
 test/tools/runner/vm_runner.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/tools/runner/vm_runner.ts b/test/tools/runner/vm_runner.ts
index 2e1a26a5ee..12eeb4747b 100644
--- a/test/tools/runner/vm_runner.ts
+++ b/test/tools/runner/vm_runner.ts
@@ -120,7 +120,7 @@ function loadInSandbox(filepath: string) {
   }
 
   // js-bson is allowed to use Buffer, only ./src/ is not
-  const isSourceFile = realPath.includes('/src/') || !realPath.includes('node_modules');
+  const isSourceFile = realPath.includes('/src/') && !realPath.includes('node_modules');
   const isTestFile = realPath.includes('.test.ts') || realPath.includes('.test.js');
 
   let localBuffer = Buffer;

From 7393381ec9ca35e207c9c573183c11e60f5ce49b Mon Sep 17 00:00:00 2001
From: Sergey Zelenov <sergey.zelenov@mongodb.com>
Date: Mon, 26 Jan 2026 16:16:40 +0100
Subject: [PATCH 11/12] run all change stream tests

---
 test/integration/change-streams/change_stream.test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/integration/change-streams/change_stream.test.ts b/test/integration/change-streams/change_stream.test.ts
index ce6dd80eb5..a7b8dec85c 100644
--- a/test/integration/change-streams/change_stream.test.ts
+++ b/test/integration/change-streams/change_stream.test.ts
@@ -1717,7 +1717,7 @@ describe('Change Streams', function () {
         });
       });
 
-      context.only('when set to false', () => {
+      context('when set to false', () => {
         it('converts Long values to native numbers', {
           metadata: { requires: { topology: '!single' } },
           test: async function () {

From dda52f2d1138d3777790550c1de4d127a22699c5 Mon Sep 17 00:00:00 2001
From: Sergey Zelenov <sergey.zelenov@mongodb.com>
Date: Tue, 27 Jan 2026 16:44:17 +0100
Subject: [PATCH 12/12] try to work with Buffer & instanceof across
 environments

---
 test/tools/runner/vm_runner.ts | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/test/tools/runner/vm_runner.ts b/test/tools/runner/vm_runner.ts
index 12eeb4747b..3109ac8e1a 100644
--- a/test/tools/runner/vm_runner.ts
+++ b/test/tools/runner/vm_runner.ts
@@ -126,7 +126,14 @@ function loadInSandbox(filepath: string) {
   let localBuffer = Buffer;
   if (isSourceFile && !isTestFile) {
     localBuffer = new Proxy(Buffer, {
-      get() {
+      get(target, prop, receiver) {
+        if (
+          typeof prop === 'symbol' ||
+          ['prototype', 'constructor', 'name', 'inspect'].includes(prop as string)
+        ) {
+          return Reflect.get(target, prop, receiver);
+        }
+
         throw new Error(
           `Forbidden: 'Buffer' usage is not allowed in source files. Use Uint8Array instead. File: ${realPath}`
         );
@@ -179,7 +186,15 @@ function loadInSandbox(filepath: string) {
         if (typeof value === 'function' && value.name) {
           // force instanceof to work across contexts by defining custom `instanceof` function
           Object.defineProperty(value, Symbol.hasInstance, {
-            value: (i: any) => i && (i.constructor.name === value.name || i instanceof value)
+            value: (i: any) => {
+              if (!i) return false;
+              // use isPrototypeOf to avoid triggering the 'instanceof' trap recursively
+              return (
+                i.constructor.name === value.name ||
+                Object.prototype.isPrototypeOf.call(value.prototype, i)
+              );
+            },
+            configurable: true
           });
 
           // also inject into global for easier access in tests