I am trying to write a test in jest for a react component. In this component I use a ref, which exposes the parent element inside the component.

In this way I can react on size changes of the parent in the component and do some magic.

const ChildComponent = ({parentRef}) => {
    ...variable declaration
    
    // do something when there are changes in
    useEffect(() => {
        
        let parentOffSet = parentRef.current.offsetWidth
        
        ... do some more things
        
    }, [parentRef])
    
    ... more content
}

This component is used in this way

import {useRef } from "react";
const ParentComponent = () => {

    const currentRef = useRef(null);
    return(
        <div ref={currentRef
            <ChildComponent />
        </div>
    );
}

Now I would like to test my ChildComponent in jest.

it('reders component'){
    const testRef = {current: {offsetWidth: 600}};
    render(<ChildComponent parentRef={testRef} />);
}

This test passes, but gives me a warning:

Warning: Function components cannot be given refs. Attempts to access this ref will fail. Did you mean to use React.forwardRef()?

I tried to modify my test e.g. via wrapping the <ChildComponent /> in another component in the test

const TestComponent = () => {
    const testRef = useRef();
    return(
        <div ref={testRef}>
            <ChildComponent parentRef={testRef} />
        </div>
    );
}; 

it('reders component'){
    render(<TestComponent />);
}

But this gives the same warning.

I did a search for the last couple of days on how to resolve the warning method.

Most of the time the answers I found are on the subject of how to test a ref within the component that is testet via a ‘mock’ here or here.

Or if a ref has a certain state.

But I did not find any answer on how to solve my Problem.

The error message states that there might be a forwardRef involved. However, as far as I understand a forwardRef this would be the other way arround: let the <ChildComponent> be exposed to the <ParentComponent /> via a ref.

Is there a workable way of testing such a component in jest and get rid of the warning?