我尝试测试一个新类和构造函数，我有一个configService.get。

@Injectable()
export class StripeService {
    private stripe: Stripe;

    constructor(private configService: ConfigService) {
        const secretKey = configService.get<string>('STRIPE_SECRET') || '';
        this.stripe = new Stripe(secretKey, {
            apiVersion: '2020-08-27',
        });
    }
}

这是我的测试课：

import { Test, TestingModule } from '@nestjs/testing';
import { StripeService } from './stripe.service';
import { ConfigService } from '@nestjs/config';

const mockStripe = () => ({})

describe('StripeService', () => {
  let service: StripeService;

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      providers: [StripeService,
      { provide: ConfigService, useFactory: mockStripe}
    ],
    }).compile();

    service = module.get<StripeService>(StripeService);
  });

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

当我尝试运行测试时，出现以下错误：

如果有人有解决方案的想法，我想解释一下。