Question du test Angular 4 (legacy)

import { TestBed, inject } from '@angular/core/testing';

describe('DataService', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [DataService]
    });
  });
});

import { TestBed, inject } from '@angular/core/testing';
import { DataService } from './data.service';

describe('DataService', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [DataService]
    });
  });
});

import { TestBed } from '@angular/core/testing';
import { inject } from '@angular/core';
import { DataService } from './data.service';

describe('DataService', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [DataService]
    });
  });
});