title: What's the difference between getTargetContext() and getContext (on InstrumentationRegistry)?
body: <p>I'm using the new Android Testing Support Library (<code>com.android.support.test:runner:0.2</code>) to run Instrumentation Tests
  (a.k.a Device or Emulator Tests). </p>
  
  <p>I annotate my test class with <code>@RunWith(AndroidJUnit4.class)</code> and use Android Studio to run them.</p>
  
  <p>For my test cases I need a <code>Context</code> instance. I can get it with <code>InstrumentationRegistry</code> but it has two context related methods and it's not clear what the difference is.</p>
  
  <p>What is the difference between <code>InstrumentationRegistry.getContext()</code> vs. <code>InstrumentationRegistry.getTargetContext()</code>?</p>