title: Jest beforeAll() share between multiple test files
body: <p>I have a Node.js project that I'm testing using Jest.  I have several test files that have the same setup requirement.  Previously, all these tests were in one file, so I just had a <code>beforeAll(...)</code> that performed the common setup.  Now, with the tests split into multiple files, it seems like I have to copy/paste that <code>beforeAll(...)</code> code into each of the files.  That seems inelegant - is there a better way to do this, ideally where I can just write my <code>beforeAll(...)</code>/setup logic once, and "require" it from multiple test files?  Note that there are other tests in my test suite that don't require this setup functionality, so I don't want to make <em>all</em> my tests run this setup (just a particular subset of test files).</p>