angular - *.directive.spec.ts 中的错误 TS2554

Question

我第一次运行“ng test”并得到这个错误:

src/app/_directives/head-title.directive.spec.ts(5,23) 中的错误:错误 TS2554:需要 2 个参数，但得到 0 个参数。

由于 spec.ts 文件是由 Angular 自动生成的，我不知道该怎么做......

这是我的指令:

import { Directive, ElementRef, AfterContentInit  } from '@angular/core';
import { Title } from '@angular/platform-browser';

@Directive({
  selector: '[edHeadTitle]'
})

export class HeadTitleDirective implements AfterContentInit{

  constructor(private el: ElementRef,private titleService: Title) {}

  ngAfterContentInit(){
    this.titleService.setTitle(this.el.nativeElement.innerHTML);
  }

}

这是相应的 spec.ts:

import { HeadTitleDirective } from './head-title.directive';

describe('HeadTitleDirective', () => {
  it('should create an instance', () => {
    const directive = new HeadTitleDirective();
    expect(directive).toBeTruthy();
  });
});

显然有问题的部分是“new HeadTitleDirective()”……我想应该有一些参数，但是哪些参数以及如何？

来自 package.json 的版本信息:

"devDependencies": {
    "@angular-devkit/build-angular": "~0.6.8",
    "@angular/cli": "~6.0.8",
    "@angular/compiler-cli": "^6.0.6",
    "@angular/language-service": "^6.0.6",
    "@types/jasmine": "~2.8.6",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "~8.9.4",
    "codelyzer": "~4.2.1",
    "jasmine-core": "~2.99.1",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~1.7.1",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.0",
    "karma-jasmine": "~1.1.1",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.3.0",
    "ts-node": "~5.0.1",
    "tslint": "~5.9.1",
    "typescript": "~2.7.2"
  }

Answer 1

这是基本编码。

这是你的类(class)签名:

constructor(private el: ElementRef,private titleService: Title) {}

创建它的方法如下:

const directive = new HeadTitleDirective();

你在那里使用问题吗？

要解决它，只需创建您的依赖项的模拟。

let elRefMock = {
  nativeElement: document.createElement('div')
};

let serviceMock = {
  setTitle: (title: string) => null
};

const directive = new HeadTitleDirective(elRefMock, serviceMock);