feat(core): implement native Windows sandboxing (#21807)

packages/core/src/services/sandboxedFileSystemService.test.ts

@@ -0,0 +1,133 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {
+  describe,
+  it,
+  expect,
+  vi,
+  beforeEach,
+  afterEach,
+  type Mock,
+} from 'vitest';
+import { SandboxedFileSystemService } from './sandboxedFileSystemService.js';
+import type {
+  SandboxManager,
+  SandboxRequest,
+  SandboxedCommand,
+} from './sandboxManager.js';
+import { spawn, type ChildProcess } from 'node:child_process';
+import { EventEmitter } from 'node:events';
+import type { Writable } from 'node:stream';
+
+vi.mock('node:child_process', () => ({
+  spawn: vi.fn(),
+}));
+
+class MockSandboxManager implements SandboxManager {
+  async prepareCommand(req: SandboxRequest): Promise<SandboxedCommand> {
+    return {
+      program: 'sandbox.exe',
+      args: ['0', req.cwd, req.command, ...req.args],
+      env: req.env || {},
+    };
+  }
+}
+
+describe('SandboxedFileSystemService', () => {
+  let sandboxManager: MockSandboxManager;
+  let service: SandboxedFileSystemService;
+  const cwd = '/test/cwd';
+
+  beforeEach(() => {
+    sandboxManager = new MockSandboxManager();
+    service = new SandboxedFileSystemService(sandboxManager, cwd);
+    vi.clearAllMocks();
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('should read a file through the sandbox', async () => {
+    const mockChild = new EventEmitter() as unknown as ChildProcess;
+    Object.assign(mockChild, {
+      stdout: new EventEmitter(),
+      stderr: new EventEmitter(),
+    });
+
+    vi.mocked(spawn).mockReturnValue(mockChild);
+
+    const readPromise = service.readTextFile('/test/file.txt');
+
+    // Use setImmediate to ensure events are emitted after the promise starts executing
+    setImmediate(() => {
+      mockChild.stdout!.emit('data', Buffer.from('file content'));
+      mockChild.emit('close', 0);
+    });
+
+    const content = await readPromise;
+    expect(content).toBe('file content');
+    expect(spawn).toHaveBeenCalledWith(
+      'sandbox.exe',
+      ['0', cwd, '__read', '/test/file.txt'],
+      expect.any(Object),
+    );
+  });
+
+  it('should write a file through the sandbox', async () => {
+    const mockChild = new EventEmitter() as unknown as ChildProcess;
+    const mockStdin = new EventEmitter();
+    Object.assign(mockStdin, {
+      write: vi.fn(),
+      end: vi.fn(),
+    });
+    Object.assign(mockChild, {
+      stdin: mockStdin as unknown as Writable,
+      stderr: new EventEmitter(),
+    });
+
+    vi.mocked(spawn).mockReturnValue(mockChild);
+
+    const writePromise = service.writeTextFile('/test/file.txt', 'new content');
+
+    setImmediate(() => {
+      mockChild.emit('close', 0);
+    });
+
+    await writePromise;
+    expect(
+      (mockStdin as unknown as { write: Mock }).write,
+    ).toHaveBeenCalledWith('new content');
+    expect((mockStdin as unknown as { end: Mock }).end).toHaveBeenCalled();
+    expect(spawn).toHaveBeenCalledWith(
+      'sandbox.exe',
+      ['0', cwd, '__write', '/test/file.txt'],
+      expect.any(Object),
+    );
+  });
+
+  it('should reject if sandbox command fails', async () => {
+    const mockChild = new EventEmitter() as unknown as ChildProcess;
+    Object.assign(mockChild, {
+      stdout: new EventEmitter(),
+      stderr: new EventEmitter(),
+    });
+
+    vi.mocked(spawn).mockReturnValue(mockChild);
+
+    const readPromise = service.readTextFile('/test/file.txt');
+
+    setImmediate(() => {
+      mockChild.stderr!.emit('data', Buffer.from('access denied'));
+      mockChild.emit('close', 1);
+    });
+
+    await expect(readPromise).rejects.toThrow(
+      "Sandbox Error: read_file failed for '/test/file.txt'. Exit code 1. Details: access denied",
+    );
+  });
+});