jest支持模拟javascript'；类别'；

我参与的一个项目使用jest作为nodejs服务器的测试框架。在一个控制器（称为

ControllerImTesting

）上，它会更新一个helper类的实例（我们将调用

classiswanttomock

并将其用于控制器。我已经在

classiswanttomock

本身编写了许多测试，所以当我测试

ControllerImTesting

时，我只想模拟

classiswanttomock

这很简单，我在

\uuuuMocks\uuuuuuuuuuuuuu

中创建了另一个js文件，其中包含

ClassiWantomock

的哑版本。当我在

ControllerImTesting

中新建它时，我希望它在

\uuuuuuuMocks\uuuuuuuuuuuuuu

中使用哑版本

在这一点上，我已经尝试了很多配置，但我的绝望之举是使用setMock，比如：

jest.setMock（'/path/to/real/class/I/want/to/mock'，'/path/to/dumb/version'）

这怎么会失败

但是当运行测试时，我得到了

TypeError:ClassIWantToMock不是构造函数

我查看了我的

classiswanttomock

的哑版，将样式从

const classiswanttomock=（req）=>{

更改为

class classiswanttomock{

。我得到了同样的错误，这是有意义的，因为使用es6类样式只是语法上的甜点

只是为了确认一下，在我的真实控制器中，我在它向实例发送消息的那一行上面写了一行，

console.log（classiswanttomock）

。它确实打印出了

'/path/to/dumb/version'

。它试图对它进行模拟，但无法

这是玩笑的局限吗？还是我只是没有正确地使用它？-->这应该怎么做

更新

/ClassIWantToMock.js

class ClassIWantToMock {
    constructor(stuff) {
        this.stuff = stuff
    }
    doStuff() {
        console.log('some real stuff')
    }
}
module.exports = ClassIWantToMock

class ClassIWantToMock {
    constructor(fakeStuff) {
        this.fakeStuff = fakeStuff
    }
    doStuff() {
        console.log('some fake stuff')
    }
}
module.exports = ClassIWantToMock

const ClassIWantToMock = require('./ClassIWantToMock')
class ControllerImTesting {
    static aMethod(req, res, next) {
        const helper = ClassIWantToMock('real stuff')
        helper.doStuff()
        return next()
    }
}
module.exports = ClassIWantToMock

jest.setMock('./ClassIWantToMock', './__mocks__/ClassIWantToMock')
const ControllerImTesting = require('./ControllerImTesting')

describe('basic test', () => {
    test('should work', () => {
        return ControllerImTesting.aMethod({}, {}, () => {}).then(() => {
            // expect console to display 'some fake stuff'
        })
    })
})

/\uuuuuuuuuuuuuuuu mocks\uuuuuuuu/ClassIWantToMock.js

class ClassIWantToMock {
    constructor(stuff) {
        this.stuff = stuff
    }
    doStuff() {
        console.log('some real stuff')
    }
}
module.exports = ClassIWantToMock

class ClassIWantToMock {
    constructor(fakeStuff) {
        this.fakeStuff = fakeStuff
    }
    doStuff() {
        console.log('some fake stuff')
    }
}
module.exports = ClassIWantToMock

const ClassIWantToMock = require('./ClassIWantToMock')
class ControllerImTesting {
    static aMethod(req, res, next) {
        const helper = ClassIWantToMock('real stuff')
        helper.doStuff()
        return next()
    }
}
module.exports = ClassIWantToMock

jest.setMock('./ClassIWantToMock', './__mocks__/ClassIWantToMock')
const ControllerImTesting = require('./ControllerImTesting')

describe('basic test', () => {
    test('should work', () => {
        return ControllerImTesting.aMethod({}, {}, () => {}).then(() => {
            // expect console to display 'some fake stuff'
        })
    })
})

/ControllerImTesting.js

class ClassIWantToMock {
    constructor(stuff) {
        this.stuff = stuff
    }
    doStuff() {
        console.log('some real stuff')
    }
}
module.exports = ClassIWantToMock

class ClassIWantToMock {
    constructor(fakeStuff) {
        this.fakeStuff = fakeStuff
    }
    doStuff() {
        console.log('some fake stuff')
    }
}
module.exports = ClassIWantToMock

const ClassIWantToMock = require('./ClassIWantToMock')
class ControllerImTesting {
    static aMethod(req, res, next) {
        const helper = ClassIWantToMock('real stuff')
        helper.doStuff()
        return next()
    }
}
module.exports = ClassIWantToMock

jest.setMock('./ClassIWantToMock', './__mocks__/ClassIWantToMock')
const ControllerImTesting = require('./ControllerImTesting')

describe('basic test', () => {
    test('should work', () => {
        return ControllerImTesting.aMethod({}, {}, () => {}).then(() => {
            // expect console to display 'some fake stuff'
        })
    })
})

/ControllerImTesting.spec.js

class ClassIWantToMock {
    constructor(stuff) {
        this.stuff = stuff
    }
    doStuff() {
        console.log('some real stuff')
    }
}
module.exports = ClassIWantToMock

class ClassIWantToMock {
    constructor(fakeStuff) {
        this.fakeStuff = fakeStuff
    }
    doStuff() {
        console.log('some fake stuff')
    }
}
module.exports = ClassIWantToMock

const ClassIWantToMock = require('./ClassIWantToMock')
class ControllerImTesting {
    static aMethod(req, res, next) {
        const helper = ClassIWantToMock('real stuff')
        helper.doStuff()
        return next()
    }
}
module.exports = ClassIWantToMock

jest.setMock('./ClassIWantToMock', './__mocks__/ClassIWantToMock')
const ControllerImTesting = require('./ControllerImTesting')

describe('basic test', () => {
    test('should work', () => {
        return ControllerImTesting.aMethod({}, {}, () => {}).then(() => {
            // expect console to display 'some fake stuff'
        })
    })
})

---

我过去曾使用sinon进行嘲弄；也许可以看看这一点？不知道现在还有什么其他的东西。“我也会犯同样的错误，这是有意义的，因为使用es6类样式只是语法上的甜点。”不完全正确。不能使用

new

调用箭头函数。为了能够使用

new

调用函数，需要将其声明为函数声明/表达式或类。您可能忘记导出类了吗？请发布一个更完整的示例，仅使用位和段很难提供帮助。@FelixKling补充道!