2023鐵人賽_D9_3

coupon_invalid_exception.dart

class CouponInvalidException implements Exception {}

money_not_enough_exception.dart

class MoneyNotEnoughException implements Exception {}

new_year_coupon.dart

import 'package:equatable/equatable.dart';

class NewYearCoupon extends Equatable {
  @override
  List<Object?> get props => [];
}

product.dart

import 'package:equatable/equatable.dart';

class Product extends Equatable {
  final double price;

  const Product(this.price);

  @override
  List<Object?> get props => [price];
}

product_repository.dart

import 'product.dart';

class ProductRepository {
  Future<void> purchase(Product product, coupon) async {}
}

purchase_product_service.dart

import 'package:clock/clock.dart';

import 'product_repository.dart';
import 'product.dart';
import 'money_not_enough_exception.dart';
import 'coupon_invalid_exception.dart';
import 'wallet_repository.dart';
import 'new_year_coupon.dart';

class PurchaseProductService {
  final ProductRepository productRepository;
  final WalletRepository walletRepository;

  PurchaseProductService(this.productRepository, this.walletRepository);

  Future<void> execute(Product product, NewYearCoupon? coupon) async {
    var now = clock.now();
    if (_isUseCoupon(coupon) && !_isFirstOfJanuary(now)) {
      throw CouponInvalidException();
    }

    var wallet = await walletRepository.get();
    if (product.price > wallet.money) {
      throw MoneyNotEnoughException();
    }

    productRepository.purchase(product, coupon);
  }

  bool _isFirstOfJanuary(DateTime now) => now.month == 1 && now.day == 1;

  bool _isUseCoupon(NewYearCoupon? coupon) => coupon != null;
}

purchase_product_service_test.dart

import 'package:clock/clock.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:mockito/annotations.dart';
import 'package:mockito/mockito.dart';

import 'product.dart';
import 'product_repository.dart';
import 'purchase_product_service.dart';
import 'purchase_product_service_test.mocks.dart';
import 'new_year_coupon.dart';
import 'wallet_repository.dart';
import 'wallet.dart';

@GenerateNiceMocks([MockSpec<ProductRepository>(), MockSpec<WalletRepository>()])
main() {
  test("use coupon when purchase product", () async {
    withClock(Clock.fixed(DateTime.parse('2023-01-01')), () async {
      var mockProductRepository = MockProductRepository();
      var mockWalletRepository = MockWalletRepository();

      when(mockWalletRepository.get()).thenAnswer((_) async => Wallet(100));

      var purchaseProductService = PurchaseProductService(mockProductRepository, mockWalletRepository);

      await purchaseProductService.execute(
          const Product(100),
          NewYearCoupon());

      verify(mockProductRepository.purchase(
          const Product(100),
          NewYearCoupon()),
      ).called(1);
    });
  });
}

wallet.dart

class Wallet {
  final double money;

  Wallet(this.money);
}

wallet_repository.dart

import 'wallet.dart';

class WalletRepository {
  Future<Wallet> get() async => Wallet(100);
}