react-test-renderer update method does not rerender component with new props

[joshuaellis]

• react-hooks-testing-library version: 4.0.0
• react-test-renderer version: 17.0.1
• react version: 17.0.1
• node version: 14.0.0
• npm (or yarn) version: 1.22.5 (yarn)

Reproduction:

https://github.com/joshuaellis/react-test-renderer-update-issue

Problem description:

@testing-library/react-hooks rerender function uses react-test-renderer update under the hood. The props are correctly passed to update function but the hook does not re-render with the new props so the test fails.

Suggested solution:

I think this has something to do with react-test-renderer so i've raised it with them here but also want to keep an eye on it.

The expected behavior

the last two logs (in the image above) should say:
"using func func2"
"im func 2"

[joshuaellis]

may be related to #525

[joshuaellis]

Okay, after recreating it all in react-test-renderer not using RHTL, it passes. This is the branch with the code & passing test, must be something wrong with our async utils I suppose.... Or maybe I fluked the branch – https://github.com/joshuaellis/react-test-renderer-update-issue/tree/only-use-test-renderer

[mpeyper]

Try making it

const { result, rerender } = renderHook(({ func }) =>
      usePolling({
        func,
        interval: 1000
      }),
      {
        initialProps: {
          func: func1
        }
      }
    )

[joshuaellis]

Ah stupid me. Although I am going to ask, out of my own curiousity, why do we have to do it this way? It seems in my opinion a little counter intuitive. Because if I want to add a new prop down the line that wasn't defined in the original render, it passes through correctly. Hence why I was confused.

Do you think we could/should remove it?

[joshuaellis]

Doesn't matter, i've had a deep look, it all makes sense, I now have an even further understanding of the engine we're using 🧠 I just realised the rtl way I built even uses that pattern! 🤕

[mpeyper]

If you're interested, #56 is mostly about how much I hate how we deal with changing props.

[joshuaellis]

I'll take a look, i've been trying to make my way through the issues we've got open and understand them properly 👍🏼