Testing MUI (@mui/material) autocomplete component with react-testing-library and async options simulated by a sleep

AsyncMuiAutocomplete.test.tsx

import Asynchronous from './AsyncAutocomplete';
import { render, screen, fireEvent, waitFor, prettyDOM, within } from '@testing-library/react';

describe('Async autocomplete', () => {
  it('renders options', async () => {
    render(<Asynchronous></Asynchronous>);

    await waitFor(() => expect(screen.getAllByText('Asynchronous')).toBeDefined());

    const combobox = screen.getByRole('combobox');
    console.log(prettyDOM(combobox));

    fireEvent.change(combobox, { target: { value: 'The Godfather' } });

    const listbox = await waitFor(() => screen.getByRole('listbox'), { timeout: 2000 });
    console.log(prettyDOM(listbox));

    expect(within(listbox).queryAllByRole('option').length).toBeGreaterThan(0);
  });
});

AsyncMuiAutocomplete.tsx

// courtesy of https://mui.com/material-ui/react-autocomplete/#load-on-open
// see more tests at https://github.com/mui/material-ui/blob/master/packages/mui-material/src/Autocomplete/Autocomplete.test.js

import * as React from 'react';
import TextField from '@mui/material/TextField';
import Autocomplete from '@mui/material/Autocomplete';
import CircularProgress from '@mui/material/CircularProgress';

interface Film {
  title: string;
  year: number;
}

function sleep(delay = 0) {
  return new Promise(resolve => {
    setTimeout(resolve, delay);
  });
}

export default function Asynchronous() {
  const [open, setOpen] = React.useState(false);
  const [options, setOptions] = React.useState<readonly Film[]>([]);
  const loading = open && options.length === 0;

  React.useEffect(() => {
    let active = true;

    if (!loading) {
      return undefined;
    }

    (async () => {
      await sleep(1e3); // For demo purposes.

      if (active) {
        setOptions([...topFilms]);
      }
    })();

    return () => {
      active = false;
    };
  }, [loading]);

  React.useEffect(() => {
    if (!open) {
      setOptions([]);
    }
  }, [open]);

  return (
    <Autocomplete
      id="asynchronous-demo"
      sx={{ width: 300 }}
      open={open}
      onOpen={() => {
        setOpen(true);
      }}
      onClose={() => {
        setOpen(false);
      }}
      isOptionEqualToValue={(option, value) => option.title === value.title}
      getOptionLabel={option => option.title}
      options={options}
      loading={loading}
      renderInput={params => (
        <TextField
          {...params}
          label="Asynchronous"
          InputProps={{
            ...params.InputProps,
            endAdornment: (
              <React.Fragment>
                {loading ? <CircularProgress color="inherit" size={20} /> : null}
                {params.InputProps.endAdornment}
              </React.Fragment>
            ),
          }}
        />
      )}
    />
  );
}

// Top films as rated by IMDb users. http://www.imdb.com/chart/top
const topFilms = [
  { title: 'The Shawshank Redemption', year: 1994 },
  { title: 'The Godfather', year: 1972 },
  { title: 'The Godfather: Part II', year: 1974 },
  { title: 'The Dark Knight', year: 2008 },
  { title: '12 Angry Men', year: 1957 },
  { title: "Schindler's List", year: 1993 },
  { title: 'Pulp Fiction', year: 1994 },
  {
    title: 'The Lord of the Rings: The Return of the King',
    year: 2003,
  },
  { title: 'The Good, the Bad and the Ugly', year: 1966 },
  { title: 'Fight Club', year: 1999 },
  {
    title: 'The Lord of the Rings: The Fellowship of the Ring',
    year: 2001,
  },
  {
    title: 'Star Wars: Episode V - The Empire Strikes Back',
    year: 1980,
  },
  { title: 'Forrest Gump', year: 1994 },
  { title: 'Inception', year: 2010 },
  {
    title: 'The Lord of the Rings: The Two Towers',
    year: 2002,
  },
  { title: "One Flew Over the Cuckoo's Nest", year: 1975 },
  { title: 'Goodfellas', year: 1990 },
  { title: 'The Matrix', year: 1999 },
  { title: 'Seven Samurai', year: 1954 },
  {
    title: 'Star Wars: Episode IV - A New Hope',
    year: 1977,
  },
  { title: 'City of God', year: 2002 },
  { title: 'Se7en', year: 1995 },
  { title: 'The Silence of the Lambs', year: 1991 },
  { title: "It's a Wonderful Life", year: 1946 },
  { title: 'Life Is Beautiful', year: 1997 },
  { title: 'The Usual Suspects', year: 1995 },
  { title: 'Léon: The Professional', year: 1994 },
  { title: 'Spirited Away', year: 2001 },
  { title: 'Saving Private Ryan', year: 1998 },
  { title: 'Once Upon a Time in the West', year: 1968 },
  { title: 'American History X', year: 1998 },
  { title: 'Interstellar', year: 2014 },
];