Test Bed Configuration and Injection

TestBed is Angular’s main testing utility.

It creates a testing module similar to Angular modules.

Example

import { TestBed } from "@angular/core/testing";
import { MyService } from "./my.service";

describe("MyService", () => {
  let service: MyService;

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

    service = TestBed.inject(MyService);
  });

  it("should create service", () => {
    expect(service).toBeTruthy();
  });
});

Explanation

TestBed.configureTestingModule() configures the test environment.

TestBed.inject() retrieves service instances.