Angular 5服务无法通过以下单元测试(NullInjectorError:HttpClient没有提供者!) [英] Angular 5 service failing to pass unit tests with (NullInjectorError: No provider for HttpClient!)
问题描述
运行单元测试时,我不断收到以下错误消息
I keep getting the following errors when running unit tests
Error: StaticInjectorError(DynamicTestModule)[ApiService -> HttpClient]:
StaticInjectorError(Platform: core)[ApiService -> HttpClient]:
NullInjectorError: No provider for HttpClient!
api.service.ts
import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
@Injectable()
export class ApiService {
constructor(private http: HttpClient) { }
url = './assets/data.json';
get() {
return this.http.get(this.url);
}
}
api.service.spec.ts
import { TestBed, inject } from '@angular/core/testing';
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';
import { ApiService } from './api.service';
describe('ApiService', () => {
beforeEach(() => {
TestBed.configureTestingModule({
imports: [
HttpClientTestingModule,
],
providers: [
ApiService,
],
});
});
it('should get users', inject([HttpTestingController, ApiService],
(httpMock: HttpTestingController, apiService: ApiService) => {
expect(apiService).toBeTruthy();
}
)
);
});
我不知道出了什么问题,因为我已经将HttpClient包含在api.service.ts中,该服务在浏览器中有效.
I don't understand what is going wrong as I have included HttpClient into api.service.ts, the service works in the browser.
这在名为MapComponent的组件中直接调用,在HomeComponent内部调用.
This is directly called in a component called MapComponent, and that is called inside HomeComponent.
Chrome 63.0.3239 (Mac OS X 10.13.3) HomeComponent expect opened to be false FAILED
Error: StaticInjectorError(DynamicTestModule)[ApiService -> HttpClient]:
StaticInjectorError(Platform: core)[ApiService -> HttpClient]:
NullInjectorError: No provider for HttpClient!
推荐答案
"NullInjectorError: No provider for HttpClient!"
的原因是未解决的依赖关系.在这种情况下,缺少HttpClientModule
.
The reason for "NullInjectorError: No provider for HttpClient!"
are unresolved dependencies. In this case the lack of a HttpClientModule
.
在.service.spec.ts文件中添加
In your .service.spec.ts file add
imports: [
HttpClientTestingModule,
],
您可能会注意到我写的是 HttpClientTestingModule
而不是HttpClientModule
.原因是我们不想发送实际的http请求,而是使用测试框架的Mock API.
You might notice that I wrote HttpClientTestingModule
instead of HttpClientModule
. The reason is that we don't want to send actual http requests, but rather use a Mock API of the test framework.
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