Challenges with "CUSTOM_ELEMENTS_SCHEMA" when Testing an Angular 2 Application

Question

Challenges with "CUSTOM_ELEMENTS_SCHEMA" when Testing an Angular 2 Application

When trying to write tests for my Angular 2 application, I keep encountering errors related to the selectors being used:

"): AppComponent@12:35 'tab-view' is not a known element:
1. If 'my-tab' is an Angular component, ensure that it is part of this module.
2. If 'my-tab' is a Web Component, include "CUSTOM_ELEMENTS_SCHEMA" in the '@NgModule.schemas' of this component to suppress this message. ("
    </div>
    <div class="app-body">
        [ERROR ->]<tab-view class="my-tab" [options]="tabOptions"></tab-view>
    </div> </div>

Even after adding CUSTOM_ELEMENTS_SCHEMA to my root module and all other modules, the errors persist.

What additional steps should I take to resolve this issue?
Is it necessary to include this in all modules or just the root module?
Are there any other specific changes or additions required?

javascript unit-testing angular typescript

Answer 1

Answer №1

In order to make it work, I had to also define the schemas in the TestBed.configureTestingModule method within the app.component.spec.ts file, instead of in a separate module file. Huge thanks to @camaron for the helpful advice. It would be great if the documentation clarified this aspect.

Here is the code snippet that I added to successfully implement the solution. Below are the initial lines from my app.component.spec.ts file:

import { TestBed, async } from '@angular/core/testing';
import { AppComponent } from './../app.component';
import { RouterTestingModule } from '@angular/router/testing';
import { CUSTOM_ELEMENTS_SCHEMA } from '@angular/core';

describe('AppComponent', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      schemas: [ CUSTOM_ELEMENTS_SCHEMA ],
      declarations: [AppComponent],
      imports: [RouterTestingModule]
    });
    TestBed.compileComponents();
  });

Answer 2

In order to make it work, I had to also define the schemas in the TestBed.configureTestingModule method within the app.component.spec.ts file, instead of in a separate module file. Huge thanks to @camaron for the helpful advice. It would be great if the documentation clarified this aspect.

Here is the code snippet that I added to successfully implement the solution. Below are the initial lines from my app.component.spec.ts file:

import { TestBed, async } from '@angular/core/testing';
import { AppComponent } from './../app.component';
import { RouterTestingModule } from '@angular/router/testing';
import { CUSTOM_ELEMENTS_SCHEMA } from '@angular/core';

describe('AppComponent', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      schemas: [ CUSTOM_ELEMENTS_SCHEMA ],
      declarations: [AppComponent],
      imports: [RouterTestingModule]
    });
    TestBed.compileComponents();
  });

Answer 3

Answer №2

I have found success following this method: within your spec.ts file, make sure to import your components and include them in the declarations section. In my specific case, I implemented this in about.component.spec.ts

import { async, ComponentFixture, TestBed } from '@angular/core/testing';
import { AboutComponent } from './about.component';
import { SidebarComponent } from './../sidebar/sidebar.component';
import { FooterComponent } from './../footer/footer.component';

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

  beforeEach(async(() => {
    TestBed.configureTestingModule({
       declarations: [ AboutComponent, SidebarComponent, FooterComponent ]
    })
    .compileComponents();
  }));

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

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

Answer 4

I have found success following this method: within your spec.ts file, make sure to import your components and include them in the declarations section. In my specific case, I implemented this in about.component.spec.ts

import { async, ComponentFixture, TestBed } from '@angular/core/testing';
import { AboutComponent } from './about.component';
import { SidebarComponent } from './../sidebar/sidebar.component';
import { FooterComponent } from './../footer/footer.component';

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

  beforeEach(async(() => {
    TestBed.configureTestingModule({
       declarations: [ AboutComponent, SidebarComponent, FooterComponent ]
    })
    .compileComponents();
  }));

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

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

Challenges with "CUSTOM_ELEMENTS_SCHEMA" when Testing an Angular 2 Application

Answer №1

Answer №2

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