title: "Module was not compiled for testing" error when using Swift Package Manager
body: <p>I created a Swift library with <code>swift package init --type library</code> and generated an Xcode project with <code>swift package generate-xcodeproj</code>.</p>
  
  <p>Now I'm trying to run the Test scheme in Xcode. It prints following error:</p>
  
  <pre><code>Module '&lt;title&gt;' was not compiled for testing
  </code></pre>
  
  <p>However when I run <code>swift build</code> and <code>swift test</code> in terminal, it works fine.</p>
  
  <p>I have <code>ENABLE_TESTABILITY</code> set to <code>YES</code> in all of the targets. I didn't change anything in the project except this. How can I make Xcode perform unit testing?</p>