Project 29: E-commerce Cart

Angular Engineer

Builds on these lessons

Component Task

Objective

TestBed.inject() retrieves a real service instance from the testing injector — the same way a component would get it, letting you test service logic in isolation.

You're building a shopping cart service, with a test for it.

Task: write a CartService with addItem and getCount, and a spec that injects it, adds one item, and asserts the count.

component.ts

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

@Injectable({ providedIn: 'root' })
export class CartService {
  private items: string[] = [];

  addItem(name: string) {
    this.items.push(name);
  }

  getCount() {
    return this.items.length;
  }
}

describe('CartService', () => {
  it('should track added items', () => {
    TestBed.configureTestingModule({});
    const service = TestBed.inject(CartService);
    service.addItem('Sneakers');
    expect(service.getCount()).toBe(1);
  });
});

* Hint: Correct characters turn green, incorrect ones turn red.

Compiler Output

🅰️

Compile your component to see the result

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