AvailableStocks.container.test.ts

import { beforeEach, describe, expect, it, test } from '@jest/globals';
import AvailableStock from '../src/business/state/AvailableStock';
import { inject, store } from '../src/inject';
import { viewModel } from '../src/ui/cashBalanceAndPortfolio/AvailableStock.container';

describe('AvailableStockContainer', () => {

  beforeEach(() => {
    inject({});
  });

  it('enables buy button when there is enough money to buy the stock.' +
    'It disables otherwise.', () => {
    const ibm = new AvailableStock('IBM', 'I. B. Machines', 150.00);

    // The BUY button is disabled, since we cannot buy stock when there is no money.
    store.portfolio.cashBalance.setAmount(0);
    let vm = viewModel(ibm);
    expect(vm.ifBuyDisabled).toBe(true);

    // The BUY button is disabled, since we cannot buy stock that costs 150, when there is only 100.
    store.portfolio.cashBalance.setAmount(100);
    vm = viewModel(ibm);
    expect(vm.ifBuyDisabled).toBe(true);

    // The BUY button is enabled, as we can buy stock that costs 150 when there is exactly 150.
    store.portfolio.cashBalance.setAmount(150);
    vm = viewModel(ibm);
    expect(vm.ifBuyDisabled).toBe(false);

    // The BUY button is enabled, as we can buy stock that costs 150 when there is more than 150.
    store.portfolio.cashBalance.setAmount(1000);
    vm = viewModel(ibm);
    expect(vm.ifBuyDisabled).toBe(false);
  });

  it('enables sell button when there at least 1 stock.' +
    'It disables otherwise.', () => {
    const ibm = new AvailableStock('IBM', 'I. B. Machines', 150.00);
    const aapl = new AvailableStock('AAPL', 'Apple Inc.', 150.00);

    // Cannot sell IBM when there are no stocks.
    store.portfolio.clearAll();
    let vm = viewModel(ibm);
    expect(vm.ifSellDisabled).toBe(true);

    // Cannot sell IBM, when there are only AAPL stocks.
    store.portfolio.addStock(aapl, 1);
    vm = viewModel(ibm);
    expect(vm.ifSellDisabled).toBe(true);

    // Can sell IBM, when there are IBM stocks.
    store.portfolio.addStock(ibm, 1);
    vm = viewModel(ibm);
    expect(vm.ifSellDisabled).toBe(false);
  });

  test('Buying stock.', () => {
    const ibm = new AvailableStock('IBM', 'I. B. Machines', 150.00);

    // Cash balance is 1000. There are no IBM stocks.
    expect(store.portfolio.howManyStocks(ibm.ticker)).toBe(0);
    store.portfolio.cashBalance.setAmount(1000);

    const vm = viewModel(ibm);
    vm.onBuy(); // Buy 1 share of IBM stock.

    // Cash balance decreased by the price of 1 IBM stock. Portfolio now contains 1 IBM stock.
    expect(store.portfolio.cashBalance.amount).toBe(1000 - ibm.currentPrice);
    expect(store.portfolio.howManyStocks(ibm.ticker)).toBe(1);
  });

  test('Buying stock without enough money. ' +
    'Note: In practice this error never happens, because the BUY button is disabled.', () => {
    const ibm = new AvailableStock('IBM', 'I. B. Machines', 150.00);

    // Set initial cash balance to 100, which is less than the price of IBM stock.
    store.portfolio.cashBalance.setAmount(100);

    // Try to buy 1 share of IBM stock.
    const vm = viewModel(ibm);

    // Assert that an error is thrown.
    expect(() => vm.onBuy()).toThrow('Not enough money to buy stock');
  });

  test('Selling stock.', () => {
    const ibm = new AvailableStock('IBM', 'I. B. Machines', 150.00);

    // Add 2 shares of IBM stock to the portfolio.
    store.portfolio.addStock(ibm, 2);

    // Sell 1 share of IBM stock.
    const vm = viewModel(ibm);
    vm.onSell();

    // Cash balance has increased by the price of 1 IBM stock.
    expect(store.portfolio.cashBalance.amount).toBe(ibm.currentPrice);

    // The portfolio now contains 1 IBM stock.
    expect(store.portfolio.howManyStocks(ibm.ticker)).toBe(1);
  });

  test('Selling stock that is not in the portfolio. ' +
    'Note: In practice this error never happens, because the SELL button is disabled.', () => {
    const ibm = new AvailableStock('IBM', 'I. B. Machines', 150.00);

    // Ensure the portfolio does not contain IBM stock.
    store.portfolio.clearStock(ibm.ticker);

    // Try to sell 1 share of IBM stock.
    const vm = viewModel(ibm);
    expect(() => vm.onSell()).toThrow('Cannot sell stock you do not own');
  });
});