MainActivityTestCase.java

import android.support.test.runner.AndroidJUnit4;
import android.test.suitebuilder.annotation.LargeTest;

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.Espresso.pressBack;
import static android.support.test.espresso.action.ViewActions.click;
import static android.support.test.espresso.matcher.ViewMatchers.isRoot;
import static android.support.test.espresso.matcher.ViewMatchers.withId;
import static android.support.test.espresso.matcher.ViewMatchers.withText;

import static com.pogamadores.test.action.ViewActions.waitText;

@RunWith(AndroidJUnit4.class)
@LargeTest
public class MainActivityTestCase {

  @Rule
  public ActivityTestRule<MainActivity> mActivityRule = new ActivityTestRule<>(MainActivity.class);
  
  @Test
  public void confirmAction() {
    String confirmationString = mActivityRule.getActivity().getString(R.string.confirmation);
    onView(withId(R.id.confirmation_button)).perform(click());
    onView(isRoot()).perform(waitText(confirmationString, 10000));
    pressBack();
  }
  
}

ViewAction.java

package com.pogamadores.test.action;

import android.support.test.espresso.PerformException;
import android.support.test.espresso.UiController;
import android.support.test.espresso.ViewAction;
import android.support.test.espresso.util.HumanReadables;
import android.support.test.espresso.util.TreeIterables;
import android.view.View;

import org.hamcrest.Matcher;

import java.util.concurrent.TimeoutException;

import static android.support.test.espresso.matcher.ViewMatchers.isRoot;
import static android.support.test.espresso.matcher.ViewMatchers.withText;

public class ViewActions
{

  /**
   * <p> Action to wait for a text to show on the screen
   * 
   * @param text    String that need to be searched
   * @param millis  Timeout of the search
   * 
   * @return  Formatted View Action
   */
  public static ViewAction waitText(final String text, final long millis) {
    return waitForMatcher(
        withText(text),
        millis,
        "wait for a specific view with text \"" + text + "\" during " + millis + " millis.");
  }
  
  /**
   * <p>Perform action of waiting for a specific Matcher.</p>
   *
   * <p>Code based on the answer provided by Alex K. on <a href="http://stackoverflow.com/a/22563297">stackoverflow</a>.</p>
   *
   * @param viewMatcher Matcher that need to be validated
   * @param millis      Timeout of the search
   * @param description Description of the action
   * @return  ViewAction to be used on .perform
   */
  protected static ViewAction waitForMatcher(final Matcher<View> viewMatcher, final long millis, final String description) {
    return new ViewAction() {
      @Override
      public Matcher<View> getConstraints() {
        return isRoot();
      }
  
      @Override
      public String getDescription() {
        return description;
      }
  
      @Override
      public void perform(UiController uiController, View view) {
        uiController.loopMainThreadUntilIdle();
        final long startTime = System.currentTimeMillis();
        final long endTime = startTime + millis;
  
        do {
          for (View child : TreeIterables.breadthFirstViewTraversal(view)) {
            if (viewMatcher.matches(child)) {
              return;
            }
          }
  
          uiController.loopMainThreadForAtLeast(50);
        }
        while (System.currentTimeMillis() < endTime);
  
        // timeout happens
        throw new PerformException.Builder()
            .withActionDescription(this.getDescription())
            .withViewDescription(HumanReadables.describe(view))
            .withCause(new TimeoutException())
            .build();
      }
    };
  }

}