title: How does android.unitTests.returnDefaultValues work?
body: <p>I know what having the following in an Android project's build.gradle is supposed to do.  But how does it work?  And what exactly are the default values returned?  How do they compare with "real" values?</p>
  
  <pre><code>android {
      // ...
      testOptions { 
          unitTests.returnDefaultValues = true
      }
  }
  </code></pre>