Preciso do seu apoio para a minha pergunta, por favor. Quero testar meu aplicativo de login.

Meu projeto está no Angular 5, Jasmine2.6.4Para efetuar login no sistema, sigo este código:

Passo 1. Componente HTML

<div id="container">
  <div id="login_card_container">
    <div id="login_card" class="card col s12">
      <form [formGroup]="loginForm" (ngSubmit)="onLogin()" class="col s12">
        <h1 id="form_title">Login</h1>
        <div class="row">
          <div class="input-field col s12">
            <input formControlName="username" id="username" type="text" class="validate" [ngClass]="{invalid: invalidCredentials}">
            <label for="username">Username</label>
          </div>
        </div>
        <div class="row">
          <div class="input-field col s12">
            <input formControlName="password" id="password" type="password" class="validate" [ngClass]="{invalid: invalidCredentials}">
            <label for="password" data-error="Your username/password combination is invalid">Password</label>
          </div>
        </div>
        <div id="login_button_container" class="row">
          <button id="login_button" type="submit" class="btn waves-effect waves-light" [disabled]="!loginForm.valid">
            <i class="fa fa-sign-in left"></i>
            Login
          </button>
        </div>
      </form>
    </div>
  </div>
</div>

Etapa 2: Componente TS

  onLogin() {
    this.loading = true;
    this.auth.loginByUsernameAndPassword(
      this.loginForm.controls['username'].value,
      this.loginForm.controls['password'].value)
      .subscribe(
      result => {
        if (result === true) {
          this.router.navigate(['/']);
        } else {
          this.loading = false;
          this.invalidCredentials = true;
        }
      },
      error => {
        this.loading = false;
        this.invalidCredentials = true;
      }
      );
  }

Etapa 3. Serviço

export class AuthService {
  private static readonly CURRENT_USER = 'currentUser';
  constructor(private http: Http, private router: Router) {
    this.currentUser = this.loadCurrentUser();
  }
  public loginByUsernameAndPassword(username: string, password: string): Observable<boolean> {
    let urlSearchParams = new URLSearchParams();
    urlSearchParams.append('username', username);
    urlSearchParams.append('password', password);
    urlSearchParams.append('user_uniqueIdid', '0');
    urlSearchParams.append('session_id', '0');
    let body = urlSearchParams.toString();
    let headers = new Headers();
    headers.append('Content-Type', 'application/x-www-form-urlencoded');

    return this.http.post(Api.getUrl(Api.URLS.Login), body, {
      headers: headers
    })
      .map((response: Response) => {
        let res = response.json();
        if (res.StatusCode === 0 && res.Token) {
          this.currentUser = {
            username: username,
            token: res.Token,
            role: res.StatusDescription.Role
          }
          localStorage.setItem(AuthService.CURRENT_USER, JSON.stringify(this.currentUser));
          return true;
        }else {
          return false;
        }
      });
  }

  public isAuthenticated(): boolean {
    let currentUser: any = localStorage.getItem(AuthService.CURRENT_USER);
    if (currentUser !== null) {
      try {
        currentUser = JSON.parse(currentUser);
        if (!currentUser.username !== undefined &&
          !currentUser.token !== undefined &&
          !currentUser.permission !== undefined) {
          return true;
        }
      } catch (ex) {
      }
    }
    return false;
  }
  public getCurrentUser(): any {
    return this.currentUser;
  }

  private loadCurrentUser(): any {
    let currentUser: any = localStorage.getItem(AuthService.CURRENT_USER);
    if (currentUser !== null) {
      try {
        currentUser = JSON.parse(currentUser);
        if (!currentUser.username !== undefined &&
          !currentUser.token !== undefined &&
          !currentUser.permission !== undefined) {
          return currentUser;
        }
      } catch (ex) {
      }
    }

    return null;
  }

}

Esse código funciona perfeitamente, como testar isso?

Esta é a minha primeira tentativa, mas é muito pobre.

Mostrar apenas: Executado 0 de 0 ERRO (0,04 segundos / 0 segundos)

describe('Component: Login', () => {
    let comp: LoginComponent
    let fixture: ComponentFixture<LoginComponent>;
    let de: DebugElement;
    let el: HTMLElement;    
    beforeEach(async(() => {
            TestBed.configureTestingModule({
            declarations: [LoginComponent],
            imports: [
                BrowserModule,
                FormsModule,
                ReactiveFormsModule,
                RouterTestingModule
            ]
        }).compileComponents().then(() => {
            fixture = TestBed.createComponent(LoginComponent);
            comp = fixture.componentInstance;
            de = fixture.debugElement.query(By.css('form'));
            el = de.nativeElement;
        });
    }));
});

ATUALIZAR:

Este código foi bem-sucedido, mas não consigo postar nome de usuário e senha. Como postar e nome de usuário: 'user' senha: '123'?

describe('Component: Login', () => {
    let component: LoginComponent;
    let fixture: ComponentFixture<LoginComponent>;

    beforeEach(() => {
        TestBed.configureTestingModule({
            imports: [ReactiveFormsModule, FormsModule, HttpModule, RouterTestingModule],
            declarations: [LoginComponent],
            providers: [AuthService],
        });
        fixture = TestBed.createComponent(LoginComponent);
        component = fixture.componentInstance;
        component.ngOnInit();
    });
    it('should call auth login method', async(() => {
        let loginElement: DebugElement;
        let debugElement = fixture.debugElement;
        let authService = debugElement.injector.get(AuthService);
        let loginSpy = spyOn(authService, 'loginByUsernameAndPassword').and.callThrough();
        loginElement = fixture.debugElement.query(By.css('form'));
        loginElement.triggerEventHandler('ngSubmit', null);
        expect(loginSpy).toHaveBeenCalledTimes(1);
    }));
});