ecommerce-escalation v1 test

service.spec.js

import {jest} from '@jest/globals';

import Service, {InsufficientStock} from './service';

describe('checkout', () => {
  test('fails when insufficient stock for desired product', async () => {
    const repository = {
      findInventoryByProductSku: jest.fn()
        .mockResolvedValueOnce({
          productSku: 'some product sku',
          stock: 2
        }),
      updateInventoryStockByProductSku: jest.fn(),
      createOrder: jest.fn()
    };

    const service = Service(repository);

    await expect(service.checkout([
      {
        productSku: 'some product sku',
        quantity: 10
      }
    ], 'some shipping address', 'some payment details')).rejects.toThrow(InsufficientStock);
    expect(repository.findInventoryByProductSku).toHaveBeenNthCalledWith(1, 'some product sku');
    expect(repository.updateInventoryStockByProductSku).not.toHaveBeenCalled();
    expect(repository.createOrder).not.toHaveBeenCalled();
  });

  test('creates order when all desired items are in stock', async () => {
    const repository = {
      findInventoryByProductSku: jest.fn()
        .mockResolvedValueOnce({
          productSku: 'some product sku',
          stock: 30
        }),
      updateInventoryStockByProductSku: jest.fn()
        .mockResolvedValueOnce(),
      createOrder: jest.fn()
        .mockResolvedValueOnce('some order id')
    };

    const service = Service(repository);

    const result = await service.checkout([
      {
        productSku: 'some product sku',
        quantity: 10
      }
    ], 'some shipping address', 'some payment details');

    expect(result).toBe('some order id');
    expect(repository.findInventoryByProductSku).toHaveBeenNthCalledWith(1, 'some product sku');
    expect(repository.updateInventoryStockByProductSku).toHaveBeenNthCalledWith(1, 'some product sku', 20);
    expect(repository.createOrder).toHaveBeenNthCalledWith(1, {
      lineItems: [
        {
          productSku: 'some product sku',
          quantity: 10
        },
      ],
      shippingAddress: 'some shipping address',
      paymentDetails: 'some payment details'
    });
  });
});