javascript - 用 Jest 测试匿名函数相等性

Question

有没有办法用 jest@20 测试匿名函数的相等性？

我正在尝试通过类似于以下内容的测试:

const foo = i => j => {return i*j}
const bar = () => {baz:foo(2), boz:1}

describe('Test anonymous function equality',()=>{

    it('+++ foo', () => {
        const obj = foo(2)
        expect(obj).toBe(foo(2))
    });

    it('+++ bar', () => {
        const obj = bar()
        expect(obj).toEqual({baz:foo(2), boz:1})
    });    
});

目前产生:

  ● >>>Test anonymous function equality › +++ foo

    expect(received).toBe(expected)

    Expected value to be (using ===):
      [Function anonymous]
    Received:
      [Function anonymous]

    Difference:

    Compared values have no visual difference.

  ● >>>Test anonymous function equality › +++ bar

    expect(received).toBe(expected)

    Expected value to be (using ===):
      {baz: [Function anonymous], boz:1}
    Received:
      {baz: [Function anonymous], boz:1}

    Difference:

    Compared values have no visual difference.

Answer 1

在这种情况下，如果不重写逻辑以使用命名函数，除了在测试前声明函数之外，您实际上别无选择，例如

const foo = i => j => i * j
const foo2 = foo(2)
const bar = () => ({ baz: foo2, boz: 1 })

describe('Test anonymous function equality', () => {
  it('+++ bar', () => {
    const obj = bar()
    expect(obj).toEqual({ baz: foo2, boz: 1 })
  });    
});

或者，您可以检查 obj.bar 是否为 any 函数，使用 expect.any(Function):

expect(obj).toEqual({ baz: expect.any(Function), boz: 1 })

这实际上可能更有意义，具体取决于测试的上下文。