title: Test a pull request created from a forked repo
body: <p>Let's say I own the site "stackoverflow". It's at <code>github.com/stackoverflow/main-site</code>.</p>
  
  <p>Now Jimmy creates a fork of the repo, <code>github.com/jimmy/main-site</code>.</p>
  
  <p>Jimmy then creates a pull request and submits it to my original repo. Jimmy didn't give me access to the fork though.</p>
  
  <p><strong>How can I test the PR locally?</strong> </p>
  
  <p>Github gives these instructions:</p>
  
  <pre><code>Step 1. From your project repository, checkout a new branch and test the changes.
  
  git checkout -b sweet-awesome-changes master
  </code></pre>
  
  <p>That works fine. I've just created a branch <code>sweet-awesome-changes</code> locally.</p>
  
  <p>Next Github says this:</p>
  
  <pre><code>git pull git@github.com:jimmy/main-site.git sweet-awesome-changes
  </code></pre>
  
  <p>But when I do that, I get an error that the repository isn't found:</p>
  
  <pre><code>ERROR: Repository not found.
  fatal: Could not read from remote repository.
  
  Please make sure you have the correct access rights
  and the repository exists.
  </code></pre>
  
  <p>What should I do?</p>