如何用玩笑测试对同一函数的特定调用序列 [英] How to test a specific sequence of calls to the same function with jest

问题描述

我正在尝试测试一个类，该类在玩笑中对模拟函数进行了一系列调用:

I have a class I'm trying to test that makes a sequence of calls to a mock function in jest:

我有一个Gpio类构造函数的模拟，该模拟在这些属性后面创建对象实例.模拟类具有用于digitalWrite的模拟方法:

I have a mock for the Gpio class constructor that creates the object instances behind these properties. The mock class has a mock method for digitalWrite:

运行测试时，我可以看到对digitalWrite的调用顺序:

And when I run my test I can see the sequence of calls made to digitalWrite:

但是我不知道如何测试顺序是否正确.我觉得如果我可以看到测试失败提示中的序列，我应该能够说先呼叫0，然后呼叫0，然后呼叫1"，但我不太清楚该怎么做它.有什么想法吗?

But I can't figure out how to test that the sequence is correct. I feel like if I can see the sequence in the test fail hint I should be able to say "call first with a 0, then with a 0, then with a 1", but I can't quite figure out how to do it. Any ideas?

也不要这样指出:我知道从技术上讲每个引脚实例都应该是独立的，并且我应该能够分别测试它们，但是以开玩笑的方式嘲笑构造方法，我必须使用digitalWrite具有相同的模拟功能.

Also so that it doesn't get pointed out: I know that technically each of the pin instances should be separate and I should be able to test them individually, but with the way you mock constructors in jest I have to use the same mock function for digitalWrite.

推荐答案

您可以使用jest的

You can use jest's .toHaveBeenNthCalledWith()

例如

it('should be called in the following sequence', () => {
  expect(......digitalWrite).toHaveBeenNthCalledWith(1, 0)
  expect(......digitalWrite).toHaveBeenNthCalledWith(2, 0)
  expect(......digitalWrite).toHaveBeenNthCalledWith(3, 1)
})

或者您可以使用模拟功能的 mock.calls 属性:

or you can use the mock function's mock.calls property:

it('should be called in the following sequence', () => {
  expect(......digitalWrite).toHaveProperty('mock.calls', [
    [0], [0], [1]
  ])
})

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