perform testing for Fragments in Android

I want to test Fragment.I am able to test Instrumentation test only. I want to perform click and set values for the textview. How can it is possible. Here is my code.Please any one help me to resolve this issue.

 @RunWith(AndroidJUnit4.class)
 public class LearnFactAdditionTest extends 
  ActivityInstrumentationTestCase2<MainActivity> {
 private MainActivity testingActivity;
  private Learn_FactsFragment testFragment;

public LearnFactAdditionTest() {
    super(MainActivity.class);
}

@Override
protected void setUp() throws Exception {
    super.setUp();


    testingActivity = getActivity();

    testFragment = new Learn_FactsFragment();
    testingActivity.getFragmentManager().beginTransaction().add(R.id.frag,testFragment,null).commit();

    getInstrumentation().waitForIdleSync();
}

@Test
public void testGameFragmentsTextViews() {

    String empty = "";

    TextView textView = (TextView)testFragment.getView().findViewById(R.id.txt_first_num_add);
    assertTrue("Empty stuff", (textView.getText().equals(empty)));
}

public void testMainThread_operations() {
    Espresso.onView(ViewMatchers.withId(R.id.txt_first_num_add))
            .perform(ViewActions.typeText("Hi"));
}

}

I am getting error like this No instrumentation registered! Must run under a registering instrumentation.