title: No tests found in <package> when testing with Espresso
body: <p>I want to test my <code>MainActivity</code> in my Android application. So, I created a first test case which tests the functionality of a button. If the user clicks this particular button, a new Activity should open.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>@RunWith(AndroidJUnit4.class)
  public class MainActivityTest {
  
      @Rule
      public ActivityTestRule&lt;MainActivity&gt; mActivityRule = new ActivityTestRule&lt;&gt;(MainActivity.class);
  
      @Test
      public void startNewActivityTest() {
          Intents.init();
          onView(withId(R.id.main_new)).perform(click());
          intended(hasComponent(NewActivity.class.getName()));
          Intents.release();
      }
  
      @Before
      public void setup() {
          closeSoftKeyboard();
      }
  
  }
  </code></pre>
  
  <p>Unfortunately, I get the following exception:</p>
  
  <pre><code>junit.framework.AssertionFailedError: No tests found in package.MainActivityTest
  at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:191)
  at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:176)
  at android.test.InstrumentationTestRunner.onStart(InstrumentationTestRunner.java:554)
  at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1701)
  </code></pre>
  
  <p>Here is my Gradle file:</p>
  
  <pre><code>apply plugin: 'com.android.application'
  
  android {
      compileSdkVersion 19
      buildToolsVersion "23.0.1"
  
      lintOptions {
          abortOnError false
      }
  
      defaultConfig {
          applicationId "package"
          minSdkVersion 14
          targetSdkVersion 19
      }
  
      signingConfigs {
          debug {
              storeFile file(RELEASE_STORE_FILE)
              storePassword RELEASE_STORE_PASSWORD
              keyAlias RELEASE_KEY_ALIAS
              keyPassword RELEASE_KEY_PASSWORD
          }
          release {
              storeFile file(RELEASE_STORE_FILE)
              storePassword RELEASE_STORE_PASSWORD
              keyAlias RELEASE_KEY_ALIAS
              keyPassword RELEASE_KEY_PASSWORD
          }
      }
      compileOptions {
          sourceCompatibility JavaVersion.VERSION_1_7
          targetCompatibility JavaVersion.VERSION_1_7
      }
  }
  
  dependencies {
      compile 'com.android.support:support-v4:19.1.0'
      compile 'com.google.android.gms:play-services:4.2.+'
      androidTestCompile 'com.android.support:support-annotations:19.0.1'
      androidTestCompile 'com.android.support.test:runner:0.4.1'
      androidTestCompile 'com.android.support.test:rules:0.4.1'
      androidTestCompile 'com.android.support.test.espresso:espresso-core:2.2.1'
      // Set this dependency if you want to use Hamcrest matching
      androidTestCompile 'org.hamcrest:hamcrest-library:1.3'
      androidTestCompile 'com.android.support.test.espresso:espresso-intents:2.2.1'
  }
  </code></pre>