package <your_package>;

import android.support.test.espresso.intent.rule.IntentsTestRule;
import android.support.test.runner.AndroidJUnit4;
import android.test.suitebuilder.annotation.LargeTest;

import org.junit.After;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;

import static android.support.test.espresso.intent.Intents.intended;
import static android.support.test.espresso.intent.matcher.ComponentNameMatchers.hasShortClassName;
import static android.support.test.espresso.intent.matcher.IntentMatchers.hasComponent;
import static <your_package>.ScreenRobot.withRobot;
import static org.junit.Assert.assertNotNull;

@RunWith( AndroidJUnit4.class )
@LargeTest
public class LoginActivityTest {
  
    private static final String TEST_EMAIL = "annyce@mycompany.com";
    private static final String TEST_PASSWORD = "123456";
    private static final String PACKAGE_NAME = "my.package";

    @Rule
    public IntentsTestRule<LoginActivity> activityRule =
            new IntentsTestRule<>( LoginActivity.class );

    @Test
    public void shouldHaveUsernameAndPasswordHeader () {
        withRobot( LoginScreenRobot.class )
                .checkAreHeadersDisplayed();
    }

    @Test
    public void shouldNotAllowLoginWhenInvalid () {
        withRobot( LoginScreenRobot.class )
                .provideActivityContext( activityRule.getActivity() )
                .callLogin( "", "" )
                .checkIsInErrorState();
    }

    @Test
    public void shouldProceedLoginWhenValid () {
        withRobot( LoginScreenRobot.class )
                .callLogin( TEST_EMAIL, TEST_PASSWORD )
                .checkIsLoggedIn();
    }

    public static class LoginScreenRobot extends ScreenRobot<LoginScreenRobot> {
      
        public LoginScreenRobot checkIsLoggedIn () {
            intended( hasComponent( hasShortClassName( PACKAGE_NAME ) ) );
            return this;
        }

        public LoginScreenRobot checkIsInErrorState () {
            return checkDialogWithTextIsDisplayed( R.string.login_error );
        }

        public LoginScreenRobot checkAreHeadersDisplayed () {
            return checkIsDisplayed( R.id.login_username_header, R.id.login_password_header );
        }

        public LoginScreenRobot callLogin (String username, String password) {
            return enterTextIntoView ( R.id.login_username_entry, username )
                    .enterTextIntoView ( R.id.login_password_entry, password )
                    .clickOkOnView( R.id.login_button );
        }
    }
}