title: MultiDexTestRunner does not work with MultiDexApplication
body: <p>I'm using:</p>
  
  <ul>
  <li>Android Studio 1.1.0  </li>
  <li>Gradle 2.2.1 </li>
  <li>Android Plugin for Gradle: 1.1.0</li>
  </ul>
  
  <p>We have recently moved to Android Studio and we are trying to make our instrument test work. However when I run the test, it gives me error </p>
  
  <p>Running tests
  Test running startedTest running failed: Unable to find instrumentation info for: ComponentInfo{com.xxx.xxx.test/android.test.InstrumentationTestRunner}
  Empty test suite.</p>
  
  <p>I am not sure what I am doing wrong here. Please see config below:</p>
  
  <p><strong>Application class:</strong></p>
  
  <pre><code>public class XxxApp extends MultiDexApplication
  {
  ...
  }
  </code></pre>
  
  <p><strong>App build.gradle</strong></p>
  
  <pre><code>apply plugin: 'com.android.application'
  
  dependencies {
      compile fileTree(dir: 'libs', include: '*.jar')
      compile 'com.google.android.gms:play-services-base:6.5.87'
      compile 'com.google.android.gms:play-services-maps:6.5.87'
      compile 'com.android.support:appcompat-v7:21.0.3'
      compile 'com.android.support:multidex:1.0.0'
      compile 'org.apache.commons:commons-lang3:3.3.2'
      compile 'com.google.code.gson:gson:2.3.1'
      compile 'joda-time:joda-time:2.7'
      compile 'org.roboguice:roboguice:2.0'
      compile project(':Common')
      compile project(':zxing-lib')
      androidTestCompile fileTree(dir: 'test-libs', include: '*.jar')
      androidTestCompile('com.android.support:multidex-instrumentation:1.0.1') {
          exclude group: 'com.android.support', module: 'multidex'
      }
      androidTestCompile 'com.google.dexmaker:dexmaker:1.+'
      androidTestCompile 'com.google.dexmaker:dexmaker-mockito:1.+'
      androidTestCompile 'junit:junit:4.11'
      androidTestCompile 'org.hamcrest:hamcrest-library:1.3'
      androidTestCompile 'org.mockito:mockito-core:1.9.5'
  }
  
  android {
      compileSdkVersion 21
      buildToolsVersion "21.1.1"
      enforceUniquePackageName false
      dexOptions {
          javaMaxHeapSize "4g"
      }
      defaultConfig {
          minSdkVersion 14
          targetSdkVersion 21
          applicationId "com.xxx.xxx"
          multiDexEnabled true
          testApplicationId "com.xxx.xxx.test"
          testInstrumentationRunner 'android.test.InstrumentationTestRunner'
          // Does not work testInstrumentationRunner 'com.android.test.runner.MultiDexTestRunner'
      }
      packagingOptions {
          exclude 'META-INF/LICENSE.txt'
          exclude 'META-INF/NOTICE.txt'
          exclude 'LICENSE.txt'
      }
      lintOptions {
          abortOnError false
          checkReleaseBuilds false
      }
      sourceSets {
          main {
              manifest.srcFile 'AndroidManifest.xml'
              java.srcDirs = ['src']
              resources.srcDirs = ['src']
              aidl.srcDirs = ['src']
              renderscript.srcDirs = ['src']
              res.srcDirs = ['res']
              assets.srcDirs = ['assets']
          }
  
          // Move the tests to tests/java, tests/res, etc...
          androidTest.setRoot('tests')
          androidTest.java.srcDir('tests/src')
          androidTest.res.srcDir('tests/res')
          androidTest.assets.srcDirs('tests/assets')
  
          // Move the build types to build-types/&lt;type&gt;
          // For instance, build-types/debug/java, build-types/debug/AndroidManifest.xml, ...
          // This moves them out of them default location under src/&lt;type&gt;/... which would
          // conflict with src/ being used by the main source set.
          // Adding new build types or product flavors should be accompanied
          // by a similar customization.
          debug.setRoot('build-types/debug')
          release.setRoot('build-types/release')
      }
      productFlavors {
      }
  }
  </code></pre>
  
  <p><strong>Test class</strong></p>
  
  <pre><code>public class XxxTests extends InstrumentationTestCase
  {
     public void testXxx()
     {
      ...
     }
  }
  </code></pre>
  
  <p><strong>Top level build.gradle</strong></p>
  
  <pre><code>dependencies 
  {
          classpath 'com.android.tools.build:gradle:1.1.0+'
  }
  </code></pre>