title: How to restore a mock created with jest.mock()?
body: <p>Apparently mock.mockRestore() does not restore the original implementation of a mock created using jest.mock()</p>
  
  <pre><code>// a.js
  export default class A {}
  
  
  // b.js
  import A from './a';
  export default class B extends A {}
  
  
  // test.js
  import A from './a';
  import B from './b';
  
  jest.mock('./a');
  jest.mock('./b');
  
  const b = new B();
  
  test('instanceOf', () =&gt; {
      A.mockRestore();
      B.mockRestore();
      expect(b).toBeInstanceOf(A); // fails
  });
  </code></pre>