javascript - Mocha测试-解决assertion_error

Question

我正在练习使用 Mocha 和类(class)。我正在编写一些成功的测试，直到遇到断言错误，这是我仍然不太熟悉的事情。

我的 test.js 文件如下，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，我试图找出为什么会出现断言错误并修复它。

Answer 1

如果你喜欢这个

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}。很明显，我们可以看到不存在价格因素。因此它返回 false。我认为这就是你的断言失败的原因。

如果您只想设置价格元素，则可以执行 x = new Payment(null,null,"50.00") 或 x = new Payment("","","50.00")