title: Android instrumented test no tests found
body: <p>I am new to Android instrumented unit tests. I have a simple test that looks like this. This is in instrumented tests; before I really write an actual instrumented test, I just want to test a simple one:</p>
  
  <pre><code>@RunWith(AndroidJUnit4.class)
  @SmallTest
  public class AddressBookKeepingInstrumentedTest {
  
  
      public static final String TEST_STRING = "This is a string";
      public static final long TEST_LONG = 12345678L;
  
      @Test
      public void test_simple() {
          assertEquals(2,1+1);
      }
  }
  </code></pre>
  
  <p>When I run this, I get the following error:</p>
  
  <pre><code>junit.framework.AssertionFailedError: No tests found in com.example.myfirstapp.AddressBookKeepingInstrumentedTest
  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:1729)
  
  Tests ran to completion.
  </code></pre>
  
  <p>Gradle build passed with success before this. 
  Any ideas why this is happening?</p>