Question

我正在尝试使用mocha框架的简单测试用例

我写过简单的打字稿

class Rectangle {
    constructor(width, height) {
        this.width = width;
        this.height = height;
    }

    get height() {
        return this.height;
    }

    set height(value) {
        if (typeof value !== 'number') {
            throw new Error('"height" must be a number.');
        }

        this.height = value;
    }

    get width() {
        return this.width;
    }

    set width(value) {
        if (typeof value !== 'number') {
            throw new Error('"width" must be a number.');
        }

        this.width = value;
    }


    get area() {
        return this.width * this.height;
    }


    get circumference() {
        return 2 * this.width + 2 * this.height;
    }
}

var rectangle= new Rectangle(10,20);
module.exports = Rectangle;

但是在尝试编写测试用例时如下：

"use strict"
require('babel-register')({
    presets: ['es2015']
});
// Import chai.
import * as chai from 'chai';
var path = require('path');

// Import the Rectangle class.
let Rectangle = require(path.join(__dirname, '..', 'rectangle.js'));
const should = chai.should;
var expect = require('chai').expect;
describe('Rectangle', () => {
    describe('#width', () => {
        let rectangle;

        beforeEach(() => {
            // Create a new Rectangle object before every test.
            rectangle = new Rectangle(10, 20);
        });

        it('returns the width', () => {
            // This will fail if "rectangle.width" does
            // not equal 10.
            rectangle.width.should.equal(10);
        });

    });
});

但测试用例失败

我不明白这里的错误

任何帮助将不胜感激

Answer 1

如果您查看docs for Should，您会看到：

var should = require（＆＃39; chai＆＃39;）。should（）// 实际调用函数

所以你的代码需要看起来像这样：

import * as chai from 'chai';
...
const should = chai.should();

此外，在您的情况下，您无需使用path，您应该可以这样做：

let Rectangle = require('../rectangle.js');

Answer 2

您显示的错误是由无限递归引起的。您应该将包含setter和getters 的实际值的变量命名为setter和getter本身。。以下是width：

的示例
class Rectangle { private _width: number; constructor(width: number) { this._width = width; } get width(): number { return this._width; } set width(value: number) { this._width = value; } } const rectangle = new Rectangle(10); console.log(rectangle.width); rectangle.width = 100; console.log(rectangle.width); // Cannot do this, as it won't compile: rectangle.width = "platypus";

否则，使用你的代码，当构造函数执行this.width = ...时，调用setter，this.width = ...再次调用setter，再次，再次调用...

Nitzan是正确的，您必须致电 chai.should()，而不仅仅是访问它。

尝试使用mocha和chai时测试用例失败

2 个答案: