How can I test async functions using Testing Library?

How can I test async functions using Testing Library?

You can test async functions in Testing Library by using the waitFor utility or by using findBy queries.

Can you give me an example of using waitFor?

Sure! You can use waitFor to wait for a specific condition to be met, like this:

await waitFor(() => {
  expect(screen.getByText(/loading/i)).toBeInTheDocument();
});

What about using findBy queries?

findBy queries are great for async operations. For example:

const element = await screen.findByText(/loaded/i);
expect(element).toBeInTheDocument();

Are there any performance considerations I should be aware of?

Yes, using waitFor can lead to longer test times if not used carefully. Always try to use the most specific queries.