javascript - 测试未返回预期结果 - 售票员套路

Question

我正在尝试通过一些套路来练习我的 javascript 测试。我不太明白为什么这不起作用，我设法用类似的销售功能很容易地做了一个 ruby​​ 版本。

ticketClark.js

var TicketClerk = function() {
  this.till = { 25: 0, 50: 0, 100: 0 };
};

TicketClerk.prototype.sell = function(array) {
  for (var i = 0; i < array.length; i++) {
    if (this.canMakeChange(array[i])) {
      this.giveChange(array[i]);
    } else {
      return "NO";
    }
  }
  return "YES";
};

TicketClerk.prototype.canMakeChange = function(note) {
  if (note === 50) {
    return this.till[25] > 0;
  }
  if (note === 100) {
    return this.canGiveFiftyTwentyFive() || this.canGiveThreeTwentyFives();
  }
  return true;
};

TicketClerk.prototype.giveChange = function(note) {
  if (note === 25) {
    this.till[25]++;
  }
  if (note === 50) {
    this.till[25]--;
    this.till[50]++;
  }
  if (note === 100 && this.canGiveFiftyTwentyFive()) {
    this.till[25]--;
    this.till[50]--;
    this.till[100]++;
  }
  if (note === 100 && this.canGiveThreeTwentyFives()) {
    this.till[25] -= 3;
    this.till[100]++;
  }
};

TicketClerk.prototype.canGiveThreeTwentyFives = function() {
  return this.till[25] > 2;
};

TicketClerk.prototype.canGiveFiftyTwentyFive = function() {
  return this.till[25] > 0 && this.till[50] > 0;
};

测试.js

describe("#TicketClerk", function() {
  beforeEach(function() {
    ticketClerk = new TicketClerk();
  });
  describe("#initialize", function() {
    it("shows a hash of the money in the till, which starts with zero of each denominator", function() {
      expect(ticketClerk.till).toEqual({ 25: 0, 50: 0, 100: 0 });
    });
  });

  describe("#sell", function() {
    it("entering 25, 25, 50 should return 'YES' as it can give change", function() {
      ticketClerk.sell([25, 25, 50, 50]);
      expect(ticketClerk.sell).toEqual("YES");
    });
    it("entering 50, 25, 50 should return 'NO' as it cannot give change", function() {
      ticketClerk.sell([50, 25, 50]);
      expect(ticketClerk.sell).toEqual("NO");
    });
  });
});

我遗漏了其他测试，我认为没有必要。 Kata 是关于接受 25 美元的电影票，并为一系列顾客找零。如果你可以给每个人零钱，它应该返回“YES”，如果不能，它应该返回“NO”。

Answer 1

您正在将方法名称而不是调用结果传递到 expect 语句中。您可以像这样简单地更改它:

describe("#TicketClerk", function() {
  beforeEach(function() {
    ticketClerk = new TicketClerk();
  });
  describe("#initialize", function() {
    it("shows a hash of the money in the till, which starts with zero of each denominator", function() {
      expect(ticketClerk.till).toEqual({ 25: 0, 50: 0, 100: 0 });
    });
  });

  describe("#sell", function() {
    it("entering 25, 25, 50 should return 'YES' as it can give change", function() {
      const result = ticketClerk.sell([25, 25, 50, 50]); // pass result
      expect(result).toEqual("YES");
    });
    it("entering 50, 25, 50 should return 'NO' as it cannot give change", function() {
      const result = ticketClerk.sell([50, 25, 50]); // pass result
      expect(result).toEqual("NO");
    });
  });
});