Disallow manually importing from __mocks__ (no-mocks-import)

When using jest.mock, your tests (just like the code being tested) should import from ./x, not ./__mocks__/x. Not following this rule can lead to confusion, because you will have multiple instances of the mocked module:

jest.mock('./x');
const x1 = require('./x');
const x2 = require('./__mocks__/x');

test('x', () => {
  expect(x1).toBe(x2); // fails! They are both instances of `./__mocks__/x`, but not referentially equal
});

Rule details

This rule reports imports from a path containing a __mocks__ component.

Example violations:

import thing from './__mocks__/index';
require('./__mocks__/index');
require('__mocks__');