Mocha测试求解assertion_error

Question

我正在练习使用Mocha和classes。我正在写一些测试，这些测试都是成功的，直到我遇到一个断言错误，这是我仍然不太熟悉的东西。

我的test.js文件如下所示，从几个类开始：

var assert = require('assert');

class Payment 
{
  constructor (name,card,price) 
  {
  this.name = name;
  this.card = card;
  this.price = price;
  }
}

class BillingService 
{
  processPayment(payment) 
  {
    if(payment.card == "123"){return true;}
    else{return false;}
  }

  checkName(payment)
  {
    if(payment.name == "John B"){return true;}
    else{return false;}
  }

  checkTotal(payment)
  {
    if(payment.price == "50.00"){return true;}
    else{return false;}
  }
}

接下来，我开始我的测试：

describe('BillingService', function() 
{
  it('should process payment', function() 
  {
    var x = new Payment("John B", "123", "50.00");
    var billingService = new BillingService();
    var outcome = billingService.processPayment(x);
    assert.equal(true, outcome);
  });

  it('should not process payment', function() 
  { 
    var x = new Payment("John B", "xf23", "50.00");
    var billingService = new BillingService();
    var outcome = billingService.processPayment(x);
    assert.equal(false, outcome);
  });

  it('should get name', function()
  {
    var x = new Payment("John B");
    var billingService = new BillingService();
    var outcome = billingService.checkName(x);
    assert.equal(true, outcome);
  });

  it('should not get name', function()
  {
    var x = new Payment("Scarlett");
    var billingService = new BillingService();
    var outcome = billingService.checkName(x);
    assert.equal(false, outcome);
  });

  it('should return price', function()
  {
    var x = new Payment("50.00");
    var billingService = new BillingService();
    var outcome = billingService.checkTotal(x);
    assert.equal(true, outcome);
  });

  it('should not return price', function()
  {
    var x = new Payment("23.00");
    var billingService = new BillingService();
    var outcome = billingService.checkTotal(x);
    assert.equal(false, outcome);
  });
}

此时，我可以运行"mocha test“命令并开始测试。

如上所述，我取得了成功。然后，我收到了以下消息：

BillingService
✓ should process payment
✓ should not process payment
✓ should get name
✓ should not get name
1) should return price
✓ should not return price

5 passing (11ms)
1 failing

1) BillingService
   should return price:

  AssertionError [ERR_ASSERTION]: true == false
  + expected - actual

  -true
  +false

  at Context.<anonymous> (test.js:130:12)

基本上，我正在尝试找出为什么会出现断言错误并修复它。

Answer 1

如果你这样做的话

it('should return price', function()
{
var x = new Payment("50.00");
var billingService = new BillingService();
var outcome = billingService.checkTotal(x);
assert.equal(true, outcome);
});

它总是返回false作为结果。因为当您调用x = new Payment("50.00")时，它会创建{name:"50.00", card : undefined, price:undefined}。因此，很明显，我们可以看到没有价格元素。因此，它返回false。我想这就是你的断言失败的原因。

如果只想设置价格元素，则可以像x = new Payment(null,null,"50.00")或x = new Payment("","","50.00")那样进行设置