title: Error "No tests found" when running Android instrumentation tests
body: <p>I am a beginner to testing. I have created a simple test case for login activity in android studio. But I got an error and I could not solve it. Here is my test code. Help will be really appreciated.</p>
  
  <pre><code>package com.example.hassidiczaddic.testinglist;
  
  import android.app.Application;
  import android.support.test.rule.ActivityTestRule;
  import android.support.test.runner.AndroidJUnit4;
  import android.test.ActivityInstrumentationTestCase2;
  import android.test.ApplicationTestCase;
  import android.test.suitebuilder.annotation.LargeTest;
  
  import org.junit.Before;
  import org.junit.Rule;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  
  import static android.support.test.espresso.Espresso.onView;
  import static android.support.test.espresso.action.ViewActions.click;
  import static android.support.test.espresso.action.ViewActions.closeSoftKeyboard;
  import static android.support.test.espresso.action.ViewActions.typeText;
  import static android.support.test.espresso.assertion.ViewAssertions.matches;
  import static android.support.test.espresso.matcher.ViewMatchers.withId;
  import static android.support.test.espresso.matcher.ViewMatchers.withText;
  
  @RunWith(AndroidJUnit4.class)
  @LargeTest
  public class ApplicationTest {
  
      public static final String STRING_TO_BE_TYPED = "Wolfmatrix";
  
      @Rule
      public ActivityTestRule&lt;MainActivity&gt; mActivityRule = new ActivityTestRule&lt;&gt;(MainActivity.class);
  
      @Test
      public void LoginActivity() {
          onView(withId(R.id.etFName))
                  .perform(typeText(STRING_TO_BE_TYPED), closeSoftKeyboard());
          onView(withId(R.id.etLName))
                  .perform(typeText(STRING_TO_BE_TYPED), closeSoftKeyboard());
          onView(withId(R.id.btnSubmit))
              .perform(click());
          onView(withId(R.id.tvView))
              .check(matches(withText(STRING_TO_BE_TYPED)));
      }
  
  }
  </code></pre>
  
  <p>This is my error:</p>
  
  <pre><code>Running tests
  
  $ adb shell am instrument -w -r   -e debug false -e class       
  com.example.hassidiczaddic.testinglist.ApplicationTest
  com.example.hassidiczaddic.testinglist.
  test/android.test.InstrumentationTestRunner
  Client not ready yet..Test running started
  junit.framework.AssertionFailedError: No tests found in     
  com.example.hassidiczaddic.testinglist.ApplicationTest
  at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:190)
  at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:175)
  at    
  android.test.InstrumentationTestRunner.onStart
  (InstrumentationTestRunner.java:555)
  at android.app.Instrumentation$InstrumentationThread.run
  (Instrumentation.java:1619)
  Tests ran to completion.
  </code></pre>
  
  <p>Here is my gradle file:</p>
  
  <pre><code>apply plugin: 'com.android.application'
  
  android {
      compileSdkVersion 23
      buildToolsVersion "23.0.3"
  
      defaultConfig {
          applicationId "com.example.hassidiczaddic.testinglist"
          minSdkVersion 16
          targetSdkVersion 23
          versionCode 1
          versionName "1.0"
      }
  
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android.txt'),'proguard-rules.pro'
          }
      }
  
      dependencies {
          compile fileTree(dir: 'libs', include: ['*.jar'])
          testCompile 'junit:junit:4.12'
          compile 'com.android.support:appcompat-v7:23.0.1'
          // App dependencies
          compile 'com.android.support:support-annotations:23.0.1'
          compile 'com.google.guava:guava:18.0'
          androidTestCompile 'com.android.support:support-annotations:23.0.1'
          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'
      }
  }
  </code></pre>