如何对Nest拦截器进行单元测试

import { Test, TestingModule } from '@nestjs/testing';
import { MyInterceptor } from './my.interceptor';

describe('MyInterceptor', () => {
  let interceptor: MyInterceptor;

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      providers: [MyInterceptor],
    }).compile();

    interceptor = module.get<MyInterceptor>(MyInterceptor);
  });

  it('should be defined', () => {
    expect(interceptor).toBeDefined();
  });
});

describe('MyInterceptor', () => {
  // ...

  it('should intercept request and modify it', () => {
    const request = { body: 'original body' };
    const context = { switchToHttp: () => ({ getRequest: () => request }) };
    const next = { handle: () => of('response') };

    interceptor.intercept(context as any, next as any).subscribe((result) => {
      expect(result).toBe('response');
      expect(request.body).toBe('modified body');
    });
  });
});

$ npm test