unit-testing - 获取 TypeScript 类的实例？

Question

我有一些遗留代码，我想开始单元测试。这是一个像这样的类:

export class Controller {
    private something: any;

    constructor() { this.something = true; }

    public getSomething(): any { return this.something; }
}

尝试像这样使用 Mocha 对其进行单元测试:

import Controller from '../../src/Controller';

describe('Controller', () => {
    let subject: any;

    beforeEach( () => {
        subject = new Controller(); // compiler complains here
    });

    describe('getOptions()', () => {
        it('should get something', () => {
            let result: any = subject.getOptions();
            if (typeof result !== 'object') {
                throw new Error('Expected object but got ' + result);
            }
        });
    });
});

编译器提示:

[ts] Cannot use 'new' with an expression whose type lacks a call or construct signature.

如何获取 Controller 类的实例来运行测试？

Answer 1

它不起作用，因为您正尝试将 Controller 作为默认导出导入，而它不是。

尝试:

import {Controller} from '../../src/Controller';

或:

export default class Controller {

您可以在 MDN 页面上阅读更多关于一般导入的信息 here .