使用 CHAI 测试设置器和获取器

Question

我正在备考，其中一项任务是使用 Chai 和 Mocha 进行单元测试，但不太了解如何测试 class 是否具有 getter 和属性的设置方法。你能帮我吗？这是作业中的示例 class：

 class PaymentPackage {
    constructor(name, value) {
        this.name = name;
        this.value = value;
        this.VAT = 20;      // Default value    
        this.active = true; // Default value
      }

  get name() {
    return this._name;
  }

  set name(newValue) {
    if (typeof newValue !== 'string') {
      throw new Error('Name must be a non-empty string');
    }
    if (newValue.length === 0) {
      throw new Error('Name must be a non-empty string');
    }
    this._name = newValue;
  }

  get value() {
    return this._value;
  }

  set value(newValue) {
    if (typeof newValue !== 'number') {
      throw new Error('Value must be a non-negative number');
    }
    if (newValue < 0) {
      throw new Error('Value must be a non-negative number');
    }
    this._value = newValue;
  }

  get VAT() {
    return this._VAT;
  }

  set VAT(newValue) {
    if (typeof newValue !== 'number') {
      throw new Error('VAT must be a non-negative number');
    }
    if (newValue < 0) {
      throw new Error('VAT must be a non-negative number');
    }
    this._VAT = newValue;
  }

  get active() {
    return this._active;
  }

  set active(newValue) {
    if (typeof newValue !== 'boolean') {
      throw new Error('Active status must be a boolean');
    }
    this._active = newValue;
}

}

Answer 1

非常简单。你得到你的 class 的实例，然后一个一个地测试 getter/setters。

describe("The class PaymentPackage", function () {

   function getInstance () {
      return new PaymentPackage("A", 1)
   }

   it("should have a getter property 'name'", function () {
      const paymentPackage = getInstance()
      expect(paymentPackage.name).to.be.a("string").and.equal("A")
   })

   it("should have a setter property 'name'", function () {
      const paymentPackage = getInstance()
      paymentPackage.name = "B"
      expect(paymentPackage.name).to.be.a("string").and.equal("B")
   })

})

使用 CHAI 测试设置器和获取器

Test setters and getters with CHAI

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