使用Jest，我如何检查模拟函数的参数是否为函数？

I'm trying this:

我正在尝试这个:

expect(AP.require).toBeCalledWith('messages', () => {})

where AP.require is a mocked function that should receive a string and a function as the second argument.

其中AP.require是一个模拟函数,它应该接收一个字符串,一个函数作为第二个参数。

Test fails with the message:

测试失败并显示以下消息:

Expected mock function to have been called with:
  [Function anonymous] as argument 2, but it was called with [Function anonymous]

3 个解决方案

#1

To assert any function, you can you use expect.any(constructor):

要断言任何函数,您可以使用expect.any(构造函数):

So with your example it would be like this:

所以用你的例子就是这样的:

expect(AP.require).toBeCalledWith('messages', expect.any(Function))

#2

The problem is that a function is an object and comparing objects in JavaScript will fail if they are not the same instance

问题是函数是一个对象,如果它们不是同一个实例,那么比较JavaScript中的对象将会失败

() => 'test' !== () => 'test'

To solve this you can use mock.calls to check the parameters seperataly

要解决这个问题,您可以使用mock.calls来检查参数

const call = AP.require.mock.calls[0] // will give you the first call to the mock
expect(call[0]).toBe('message')
expect(typeof call[1]).toBe('function')

#3

You can use expect.any(constructor)

你可以使用expect.any(构造函数)

or if you do not care to specify the constructor, you can also use

或者如果您不关心指定构造函数,您也可以使用

expect.anything()

#1