I am trying to get to 100% coverage for my tests in one of them it highlights the onClick function which sets the state for a component: this is the component:

I have a button which has an onClick function as below, the button is mapped in from an array of objects.

  const [activeIdx, setActiveIdx] = React.useState(0);



  <button type="button" data-testid={'btn-test} 

     onClick={() => {setActiveIdx(() => index); inner.cb(index)}}key={inner.id}>

     {inner.title}</button>

This button clicks and sets the active index of the button clicked as this is a button group. How would I test the onClick function in jest/react-testing library?

I have some tests that check a few things like:

    it('Should render without crashing', (): void => {

        const div = document.createElement("div");

        ReactDOM.render(<ButtonGroup data={Data}/>, div);

        ReactDOM.unmountComponentAtNode(div);

    });



    const btn = screen.getByRole('button', {name: '1 hour'});



    it('Should be clicked', (): void => {

       fireEvent.click(btn);

       expect(btn).toBeValid();

    });

But how to mock the function and check that?