prettifyHTMLFile.test.js

//correct test for https://ru.hexlet.io/courses/js-advanced-testing/lessons/files/exercise_unit task
import os from 'os';
import path from 'path';
import { promises as fs } from 'fs';
import getFunction from '../functions.js';

const prettifyHTMLFile = getFunction();

// BEGIN (write your solution here)

let expected;
const getFixturePath = filename => path.join('__fixtures__', filename);
const src = getFixturePath('before.html');
const dest = path.join(os.tmpdir(), 'before.html');

beforeAll(async () => expected = await fs.readFile(getFixturePath('after.html'), 'utf-8'));
beforeEach(async () => await fs.copyFile(src, dest));

test('prettifyHTMLFile', async () => {  
  await prettifyHTMLFile(dest);
  const actual = await fs.readFile(dest, 'utf-8');
  expect(actual).toBe(expected);
});