title: New Android Gradle plugin 1.3 feature of separate instrumentation test module not working
body: <p>On running the instrumentation tests for module <code>test</code>, I'm getting the following error -</p>
  
  <pre><code>Test running failed: Instrumentation run failed due to 'java.lang.NoClassDefFoundError' Empty test suite.
  </code></pre>
  
  <p>I have a project with two modules : <code>app</code> and <code>test</code></p>
  
  <p>This is the <code>build.gradle</code>(test)`</p>
  
  <pre><code>apply plugin: 'com.android.test'
  
      android{
          compileSdkVersion 19
          buildToolsVersion "21.1.2"
          defaultConfig{
              testApplicationId 'com.xx.android.test'
              testInstrumentationRunner com.xx.android.test.CustomRunner'
          }
          targetProjectPath ':app'
          targetVariant 'debug'
      }
      dependencies {
          compile fileTree(include: ['*.jar'], dir: 'libs')
      }
  </code></pre>
  
  <p>&amp; this is <code>AndroidManifest.xml</code> for test module</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.xx.android.test"&gt;
      &lt;uses-sdk android:minSdkVersion="16" android:targetSdkVersion="19" /&gt;
  &lt;application&gt;
      &lt;uses-library android:name="android.test.runner" /&gt;
  &lt;/application&gt;
      &lt;instrumentation android:name=".CustomRunner"
          android:targetPackage="com.xx.android"
          android:handleProfiling="false"
          android:functionalTest="false"
          android:label="Instrumentation test"/&gt;
  &lt;/manifest&gt;
  </code></pre>