Angular 为什么我的角度测试会给出不一致的结果？

在我的angular应用程序中，我们有一个“LayoutContainer”类，它只显示我们网站的标题，然后是一个带有静态链接的导航栏

我需要能够根据登录用户的身份动态创建链接——如果他们是管理员，我希望能够显示新链接。我所做的是从“帐户”模块导入减速机

现在，我看到了单元测试的不一致性，当我按照随机顺序运行测试时，某些旧的测试正在崩溃。其他时候，所有68项测试都通过了

以下是某些组件“应创建”类偶尔弹出的错误：

Uncaught TypeError: Cannot read property 'authentication' of undefined
    at :9876/_karma_webpack_/webpack:/src/app/account/reducers/index.ts:42
    at :9876/_karma_webpack_/webpack:/node_modules/@ngrx/store/fesm5/store.js:528
    at memoized (:9876/_karma_webpack_/webpack:/node_modules/@ngrx/store/fesm5/store.js:484)
    at defaultStateFn (:9876/_karma_webpack_/webpack:/node_modules/@ngrx/store/fesm5/store.js:502)
    at :9876/_karma_webpack_/webpack:/node_modules/@ngrx/store/fesm5/store.js:531
    at memoized (:9876/_karma_webpack_/webpack:/node_modules/@ngrx/store/fesm5/store.js:484)
    at :9876/_karma_webpack_/webpack:/node_modules/@ngrx/store/fesm5/store.js:501
    at Array.map (<anonymous>)
    at defaultStateFn (:9876/_karma_webpack_/webpack:/node_modules/@ngrx/store/fesm5/store.js:501)
    at :9876/_karma_webpack_/webpack:/node_modules/@ngrx/store/fesm5/store.js:531
    at 

疯狂的是，当我重新运行它几次时，通常所有的测试都通过了。问题可能是什么

编辑--失败测试的示例

// Angular Core
import { async, ComponentFixture, TestBed } from '@angular/core/testing';

// Angular Material
import { MatDialogRef, MAT_DIALOG_DATA } from '@angular/material';

// ngrx
import { StoreModule, combineReducers } from '@ngrx/store';

// Reducers
import * as fromAccount from '../../../account/reducers';

// Component
import { CancelSubscriptionDialogComponent } from './cancel-subscription-dialog.component';

describe('CancelSubscriptionComponent', () => {
  let component: CancelSubscriptionDialogComponent;
  let fixture: ComponentFixture<CancelSubscriptionDialogComponent>;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [
        StoreModule.forRoot({
          account: combineReducers(fromAccount.reducers)
        })
      ],
      providers: [
        { provide: MatDialogRef, useValue: {} },
        {
          provide: MAT_DIALOG_DATA,
          useValue: {}
        }
      ],
      declarations: [CancelSubscriptionDialogComponent]
    }).compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(CancelSubscriptionDialogComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

  it('should create', () => {
    expect(component).toBeTruthy();
  });
});

//角形磁芯
从“@angular/core/testing”导入{async，ComponentFixture，TestBed}；
//角材料
从“@angular/material”导入{MatDialogRef，MAT_DIALOG_DATA}；
//ngrx
从'@ngrx/store'导入{StoreModule，combinereducer}；
//还原剂
从“../../../../account/reducers”导入*作为fromAccount；
//组成部分
从“./cancel subscription dialog.component”导入{CancelSubscriptionDialogComponent}；
描述（'CancelSubscriptionComponent'，（）=>{
let组件：CancelSubscriptionDialogComponent；
let夹具：组件夹具；
beforeach（异步（（）=>{
TestBed.configureTestingModule({
进口：[
StoreModule.forRoot({
帐户：组合减速机（来自帐户.减速机）
})
],
供应商：[
{provide:MatDialogRef，useValue:{}，
{
提供：MAT_DIALOG_数据，
useValue:{}
}
],
声明：[CancelSubscriptionDialogComponent]
}).compileComponents（）；
}));
在每个之前（（）=>{
fixture=TestBed.createComponent（CancelSubscriptionDialogComponent）；
组件=fixture.componentInstance；
fixture.detectChanges（）；
});
它（'应该创建'，（）=>{
expect（component.toBeTruthy（）；
});
});

这取决于您的测试在做什么。他们似乎在某种程度上共享这个国家。你能发布你的一些测试吗？当然，我编辑了这篇文章以包含其中一个测试。这取决于你的测试在做什么。他们似乎在某种程度上共享这个国家。你能发布你的一些测试吗？当然，我编辑了这篇文章以包含其中一个测试。

// Angular Core
import { async, ComponentFixture, TestBed } from '@angular/core/testing';

// Angular Material
import { MatDialogRef, MAT_DIALOG_DATA } from '@angular/material';

// ngrx
import { StoreModule, combineReducers } from '@ngrx/store';

// Reducers
import * as fromAccount from '../../../account/reducers';

// Component
import { CancelSubscriptionDialogComponent } from './cancel-subscription-dialog.component';

describe('CancelSubscriptionComponent', () => {
  let component: CancelSubscriptionDialogComponent;
  let fixture: ComponentFixture<CancelSubscriptionDialogComponent>;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [
        StoreModule.forRoot({
          account: combineReducers(fromAccount.reducers)
        })
      ],
      providers: [
        { provide: MatDialogRef, useValue: {} },
        {
          provide: MAT_DIALOG_DATA,
          useValue: {}
        }
      ],
      declarations: [CancelSubscriptionDialogComponent]
    }).compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(CancelSubscriptionDialogComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

  it('should create', () => {
    expect(component).toBeTruthy();
  });
});