Allow using `vi.mock` (and related) functions in tests

Bắt đầu với unit-test builder mới của Angular và đường dẫn bundling bằng Vite của nó, sau đó theo dõi nơi các lệnh gọi vi.mock bị từ chối và cách các tệp spec cùng setupFiles được biến đổi. Xem xét các yêu cầu được đề xuất về phát hiện tại thời điểm biên dịch, hoisting, viết lại import và mock registry. Được xem là hoàn thành khi hỗ trợ các hàm vi được liệt kê, đồng thời vẫn giữ nguyên ESM live bindings, sourcemaps, coverage và không có trình tải mô-đun lúc chạy.

Which @angular/* package(s) are relevant/related to the feature request?

core

Description

With the new Angular unit-test builder (Vite), test files are bundled into unified chunks.
Because of this full bundling step:

• ESM modules are statically linked at build time
• There is no runtime module graph available
• vi.mock() cannot intercept module loading
• Mocking entire modules (components/services/modules) is not possible

Currently if we use vi.mock function for automocking component/directives/services/pipes/etc..., we got an error:

Error: The "vi.mock" and related methods are not supported with the Angular unit-test system. Please use Angular TestBed for mocking.

TestBed overrides are insufficient because:

• They replace Angular metadata (providers/imports), not module implementation
• They cannot replace pure TS logic or side effects
• They do not intercept ESM import bindings

Proposed solution

Instead of runtime interception (like Vitest normally does), Angular test builder should:

1. Detect vi.mock() calls at compile time (in spec files, and in setupFiles)
2. Hoist them
3. Rewrite import bindings to use a generated mock registry
4. Replace module resolution during bundling

I suggest to create esbuild plugin, that:

1. Parse test file AST
2. Detect:

• vi.mock()
• vi.unmock()
• vi.doMock()
• vi.doUnmock()
• vi.importMock()
• vi.importActual()
• vi.hoisted()

3. Hoist mock calls
4. Rewrite imports

Example Transform Injectable

Before:

import { MyService } from './my-service';
import { MyOtherService } from './my-other-service';

vi.mock('./my-service', () => ({
  MyService:
    @Injectable({providedIn: 'root'})
    class {
      get() { return 'mock'; }
    }
}));

vi.mock('./my-other-service');

test(() => {
  const myService = new MyService();
  const myOtherService = new MyOtherService();
});

After:

// should initialize once in one environment
const __angularViMocks = (globalThis.__angular_vi_mocks ??= new Map<string, any>());

__angularViMocks.set(
  './my-service',
  (() => ({
    MyService: class {
      get() { return 'mock'; }
      static ɵprov = {
         providedIn: 'root',
         factory: () => new this();
      };
      static ɵfac = () => new this(); 
    }
  }))()
);

__angularViMocks.set(
  './my-other-service',
  (() => ({
    MyOtherService: class {
      get = vi.fn(); // maybe better to put `vi.fn()` to MyOtherService.prototype.get = vi.fn();
      static ɵprov = {
         providedIn: 'root',
         factory: () => new this();
      };
      static ɵfac = () => new this(); 
    }
  }))()
);

import * as __angularViActualMod1 from './my-service';
import * as __angularViActualMod2 from './my-other-service';

// We should replace that import in every dependent chunk.
const { MyService } = __angularViMocks.get('./my-service') ?? __angularViActualMod1;
const { MyOtherService } = __angularViMocks.get('./my-other-service') ?? __angularViActualMod2;

Requirements:

• Must mock full implementation (not only metadata) for any modules, as vi.mock() does
• Must stub components, services, modules, pipes, directives both metadata and implementation
• Must preserve ESM live bindings semantics
• Must preserve sourcemaps and coverage
• Must not require runtime module loader

Alternatives considered

Currently we have no choice, but stay with slow and inefficient jest + jest-preset-angular.

I've implemented deep-automocking infrastructure for jest.mock() ng-automocks-jest, it can stub any angular entities, both metadata and implementation.