Jasmine and Karma encountered a TypeError stating that the function this.role.toLowerCase is not valid

Currently, I am in the process of writing a test case for a page within an application that our team is actively developing. However, I have encountered a challenging error within one of the test cases that I am struggling to overcome. Below is my Spec file:

import { UserApiService } from 'src/app/services/api/user-apiservice';
import { MatDialog } from '@angular/material/dialog';
import { AuthenticationService } from '../../services/shared/authentication.service';

import { MainViewComponent } from './mainview.component';
import { of } from 'rxjs';

describe('MainViewComponent', () => {
  let component: MainViewComponent;
  let fixture: ComponentFixture<MainViewComponent>;
  let mockTlsApiService, mockMatDialog, mockAuthenticationService;

  beforeEach(async(() => {
    mockAuthenticationService = jasmine.createSpyObj(['getUserData','getDateData']);
    mockAuthenticationService.getUserRole = jasmine.createSpy().and.returnValue(of(['admin']));
    mockAuthenticationService.getUserRole.toLowerCase = jasmine.createSpy().and.returnValue(of(['admin']));
    mockAuthenticationService.getUserFullName = jasmine.createSpy().and.returnValue(of([]));

    TestBed.configureTestingModule({
      declarations: [ MainViewComponent ],
      providers: [
        {provide: UserApiService, useValue: mockTlsApiService},
        {provide: MatDialog, useValue: mockMatDialog},
        {provide: AuthenticationService, useValue: mockAuthenticationService},
      ],
    })
    .compileComponents();
  }));

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

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

The section of code that triggers the error message during testing is as follows:

  constructor(    
    private repoService: UserApiService,
    public dialog: MatDialog,
    private authenticationService: AuthenticationService,
  ) {
   
  }
  ngAfterViewInit(): void {
  this.dataSource.sortingDataAccessor = (item, property) => {
    switch (property) {
       case 'origDate': return new Date(item.origDate);
       default: return item[property];
    }
  };
  }
  ngOnInit(): void {
    this.getQueues();

    this.getData();

    this.toolOrderNoFilterFunc(); this.toolNoFilterFunc(); this.eclFilterFunc(); this.abbrFilterFunc(); this.seriesFilterFunc(); this.nameFilterFunc(); this.toolTypeFilterFunc();
    this.toolChangeFilterFunc(); this.ccnDesFilterFunc(); this.ccnFabFilterFunc(); this.revFilterFunc();
  }
. . .
  getQueues(){
    this.role=this.authenticationService.getUserRole();
    this.allQueues = ['ME1', 'ME2', 'Est', 'Safe', 'TFab', 'Fin', 'Acct', 'Shop Stat','Rel']
    this.userFullName = this.authenticationService.getUserFullName();
    //is it Tfab or Tool???
    if(this.role.toLowerCase().search("admin") != -1 ){
        this.arrayQueues = ['ME1', 'ME2', 'Est', 'Safe', 'TFab', 'Fin', 'Acct', 'Shop Stat','Rel']
        //this.arrayQueues = ['TFab', 'Fin', 'ME1']
    } else {
      if(this.role.toLowerCase().search("me or designer") != -1 ){
          this.arrayQueues.push('ME1')
          this.arrayQueues.push('ME2')
      }
      if(this.role.toLowerCase().search("estimating") != -1 ){
        this.arrayQueues.push('Est')
      }
      if(this.role.toLowerCase().search("saftey") != -1 ){
        this.arrayQueues.push('Safe')  //is it SAF or Safe???
      }
      if(this.role.toLowerCase().search("tool fab") != -1 ){
        //is it Tfab or Tool???
        this.arrayQueues.push('TFab') 
      }
      if(this.role.toLowerCase().search("finance") != -1 ){
        this.arrayQueues.push('Fin')
      }
      if(this.role.toLowerCase().search("accountability") != -1 ){
        this.arrayQueues.push('Acct')
      }
      if(this.role.toLowerCase().search("read only") != -1 ){
        this.arrayQueues = this.allQueues
      }
    }

    this.isempty = false;
    // console.log(this.arrayQueues)
  }

When the execution reaches the first instance of this.role.toLowerCase(), an error is triggered which is described in the title of this post.

I have attempted creating mocks for both role and toLowerCase functions, however, these attempts resulted in additional errors. I also experimented with spyOn without success.

Could you suggest a possible solution to resolve this error message?

Answer №1

After some experimentation, I decided to tweak how I was simulating the Authentication service:

mockAuthenticationService = jasmine.createSpyObj(['getUserData','getDateData']);
mockAuthenticationService.getUserRole = jasmine.createSpy().and.returnValue(of(['admin']));
mockAuthenticationService.getUserRole.toLowerCase = jasmine.createSpy().and.returnValue(of(['admin']));
mockAuthenticationService.getUserFullName = jasmine.createSpy().and.returnValue(of([]));

I revised it to this new approach:

export class mockAuthentication{
  getUserRole(){
    return "admin";
  };
  getUserFullName(){
    return "Test User";
  }
};

Additionally, I made changes to the provide statement by switching from:

{provide: AuthenticationService, useValue: mockAuthenticationService},

to:

{provide: AuthenticationService, useClass: mockAuthentication},

With these adjustments, my test now passes flawlessly. It caught me off guard because the initial method of mocking the service had proven effective in various other components within the same application.

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