我在尝试模拟类和构造函数时遇到了麻烦。
我想测试一个App.ts类:
class App {
public server: Express;
constructor() {
this.server = new Express();
this.server.init();
}
}
export default App;
对于测试场景-〉示例化App类后,它应该:- 确保创建Express类的新示例-确保调用init函数
所以我有我的App.test文件:
import App from '../App';
let mockedExp: jest.Mock;
jest.mock('../Express', () => {
return {
default: jest.fn().mockImplementation(() => {
return {
init: mockedExp,
};
}),
};
});
describe('App', () => {
beforeEach(() => {
mockedExp = jest.fn().mockImplementation();
mockedExp.mockClear();
});
it('Should call init from express with initialize', () => {
new App();
expect(mockedExp).toBeCalled();
});
});
当我运行测试时,我得到了以下结果:
TypeError: Express_1.default is not a constructor
8 |
9 | constructor() {
> 10 | this.server = new Express();
| ^
11 | this.server.init();
12 | }
特快舱位:
import express from 'express';
import Boom from 'express-boom';
import morgan from 'morgan';
import Locals from './Locals';
import Middleware from './Middleware';
import Logger from './Logger';
export default class Express {
public app: express.Application;
constructor() {
this.app = express();
// disable the x-powered-by header
this.app.disable('x-powered-by');
this.app.locals = Locals.getConfig();
// add boom
this.app.use(Boom());
this.app.set('logger', Logger);
// morgan logger
/* instanbul ignore next */
if (this.app.locals.env === 'production') this.app.use(morgan('combined'));
else {
this.app.use(morgan('dev'));
}
}
public init(): void {
const mid = new Middleware(this.app);
mid.addLogRoutes();
}
public start(): void {
const server = this.app.listen(this.app.locals.PORT, (error: Error) => {
if (error) {
throw new Error(`Unable to start server ${error}`);
}
/* istanbul ignore next */
console.log(`Server starting on ${server.address().port}`);
});
}
}
我使用以下打字规则:
"experimentalDecorators": true,
"emitDecoratorMetadata": true,
"esModuleInterop": true,
"allowSyntheticDefaultImports": true,
"noUnusedLocals": true /* Report errors on unused locals. */,
"noUnusedParameters": true /* Report errors on unused parameters. */,
"noFallthroughCasesInSwitch": true /* Report errors for fallthrough cases in switch statement. */,
"strict": true /* Enable all strict type-checking options. */,
"noImplicitAny": true /* Raise error on expressions and declarations with an implied 'any' type. */,
"strictNullChecks": true,
"strictFunctionTypes": true /* Enable strict checking of function types. */,
"strictBindCallApply": true /* Enable strict 'bind', 'call', and 'apply' methods on functions. */,
"noImplicitThis": true /* Raise error on 'this' expressions with an implied 'any' type. */,
"alwaysStrict": true /* Parse in strict mode and emit "use strict" for each source file. */
我做错什么了?
2条答案
按热度按时间klr1opcd1#
必须在返回的对象中指定
__esModule: true
或者,如果默认导出是唯一导出,则可以直接从工厂返回:
vsdwdz232#
对我来说,只要将
"esModuleInterop": true
添加到我的规范的ts配置中就可以解决这个问题。但是在我的用例中,我甚至没有尝试去模仿一个外部库,我希望我的测试可以运行它。下面是我编写的代码的一个例子: