1import { fs, vol } from 'memfs';
2
3import { asMock } from '../../__tests__/asMock';
4import * as Log from '../../log';
5import { FileNotifier } from '../FileNotifier';
6
7jest.mock('../../log');
8
9const originalCwd = process.cwd();
10
11beforeEach(() => {
12  vol.reset();
13});
14
15beforeAll(() => {
16  process.chdir('/');
17  // @ts-expect-error
18  fs.watchFile = jest.fn(fs.watchFile);
19});
20
21afterAll(() => {
22  process.chdir(originalCwd);
23});
24
25it('returns null when no files can be found', () => {
26  vol.fromJSON({}, '/');
27  const fileNotifier = new FileNotifier('./', ['babel.config.js']);
28  expect(fileNotifier.startObserving()).toBe(null);
29});
30
31it('observes the first existing file', () => {
32  asMock(fs.watchFile)
33    // @ts-expect-error
34    .mockImplementationOnce((_, callback) => {
35      // @ts-expect-error: polymorphism
36      callback({}, { size: 1 });
37    });
38
39  vol.fromJSON(
40    {
41      'babel.config.js': '',
42    },
43    '/'
44  );
45  const fileNotifier = new FileNotifier('./', [
46    // Skips this file
47    '.babelrc',
48    // Starts observing
49    'babel.config.js',
50  ]);
51  expect(fileNotifier.startObserving()).toBe('babel.config.js');
52
53  // We mock out the callback firing and test that a warning was logged.
54  expect(Log.log).toBeCalledTimes(1);
55  expect(Log.log).toBeCalledWith(expect.stringContaining('babel.config.js'));
56});
57