错误：模块“DynamicTestModule”导入的意外值“未定义”。 请添加@NgModule 注释

Question

I am writing unit test case using jasmine for Angular using Nebular Module. I am very new to writing test cases. From the below code when i use the fixture = TestBed.overrideComponent(..) , I am getting the error:

Error: Unexpected value 'undefined' imported by the module 'DynamicTestModule'. Please add an @NgModule annotation.

My code:

import { ComponentRef } from "@angular/core";
import { async, ComponentFixture, TestBed } from "@angular/core/testing";
import { FormControl, ReactiveFormsModule } from "@angular/forms";
import { GeneratorComponent } from "./generator.component";
import { NbToastrModule, NbOverlayModule, NbLayoutScrollService } from '@nebular/theme';
import { HttpClientTestingModule } from '@angular/common/http/testing';
import { InjectionToken } from '@angular/core';
import { Injectable } from '@angular/core';

fdescribe('GeneratorComponent', () => {
  let component: GeneratorComponent;
  let fixture: ComponentFixture<GeneratorComponent>;

  beforeEach(() => {
     TestBed.configureTestingModule({       
      declarations: [GeneratorComponent],
      imports: [
                ReactiveFormsModule,
                HttpClientTestingModule,
                NbToastrModule.forRoot(),
                NbOverlayModule.forRoot(),
                {provide: InjectionToken,useValue: '',multi: true}
              ],
      providers: [NbLayoutScrollService]
    }).compileComponents();
    fixture = TestBed.overrideComponent(GeneratorComponent, { //--Error line
      set: {
        selector: 'ngx-tabs',
        templateUrl: './fm-generator.component.html'
      }
    })
      .createComponent(GeneratorComponent);
    //fixture = TestBed.createComponent(GeneratorComponent);
    //component = fixture.componentInstance;
 });
  
  it('Test Which Application Template', () => {
    console.log("Running test script for Factory Model");
    const val = 10 * 2;
    expect(val).toBe(20);
  });
})

Where am i going wrong? When i comment the fixture = TestBed.overrideComponent(GeneratorComponent, {} ) line, My test case is getting passed. Any problem with the usage of fixture in my case?

Answer 1

You should get fixture from TestBed.createComponent method. So it should be:

TestBed.configureTestingModule({--your code--})
     .overrideComponent(--your code--)
     .compileComponents();

fixture = TestBed.createComponent(GeneratorComponent);

Also I noticed strange line in imports:

{provide: InjectionToken,useValue: '',multi: true}

it should be placed in providers, and instead of InjectionToken some token that you have created and use in component