HttpClient单元测试NullInjectorError:没有为Angular提供程序！错误

import { TestBed } from '@angular/core/testing';
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';
import { HttpClient } from '@angular/common/http';

beforeEach(() => {
  TestBed.configureTestingModule({
    imports: [HttpClientTestingModule],
    providers: [HttpClient]
  });
});

it('should make a GET request', () => {
  const httpClient = TestBed.inject(HttpClient);
  const httpTestingController = TestBed.inject(HttpTestingController);

  // 执行HTTP请求
  httpClient.get('/api/data').subscribe(response => {
    // 处理响应
    expect(response).toBeTruthy();
  });

  // 模拟HTTP响应
  const req = httpTestingController.expectOne('/api/data');
  req.flush({ data: 'test' });

  // 验证请求已完成
  httpTestingController.verify();
});