Login acceptance test

LoginIdlingResource.java

package com.dd.doordash;

import android.app.Activity;
import android.support.test.InstrumentationRegistry;
import android.support.test.espresso.IdlingResource;

import com.dd.doordash.activities.main.DashboardActivity;

public class LoginIdlingResource implements IdlingResource {

    private ResourceCallback resourceCallback;

    @Override
    public String getName() {
        return LoginIdlingResource.class.getSimpleName();
    }

    @Override
    public boolean isIdleNow() {
        Activity activity = ((DoorDashApp) InstrumentationRegistry
                .getTargetContext().getApplicationContext()).getCurrentActivity();
        boolean isIdle = activity != null && activity instanceof DashboardActivity;
        if (isIdle) {
            resourceCallback.onTransitionToIdle();
        }
        return isIdle;
    }

    @Override
    public void registerIdleTransitionCallback(ResourceCallback callback) {
        this.resourceCallback = callback;
    }
}

LoginTest.java

package com.dd.doordash;

import android.content.Intent;
import android.support.test.rule.ActivityTestRule;
import android.support.test.runner.AndroidJUnit4;

import com.dd.doordash.activities.MainActivity;
import com.dd.doordash.instruction.PostLoginInstruction;
import com.dd.doordash.util.ConditionWatcher;

import org.hamcrest.Matchers;
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.clearText;
import static android.support.test.espresso.action.ViewActions.click;
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.isDisplayed;
import static android.support.test.espresso.matcher.ViewMatchers.withId;
import static android.support.test.espresso.matcher.ViewMatchers.withTagValue;

/**
 * Test for log in flow.
 */
@RunWith(AndroidJUnit4.class)
public class LoginTest {

    private static final String TAG = LoginTest.class.getSimpleName();

    @Rule
    public ActivityTestRule<MainActivity> activityRule
            = new ActivityTestRule<>(MainActivity.class, false, false);

    @Before
    public void setup() {
        activityRule.launchActivity(new Intent());
    }

    @Test
    public void login() throws Exception {
        onView(withId(R.id.login_button)).perform(click());

        onView(withTagValue(Matchers.is("login_email")))
          .perform(clearText()).perform(typeText("login@example.com"));
        onView(withTagValue(Matchers.is("login_password")))
          .perform(typeText("login-password"));
        
        LoginIdlingResource loginIdlingResource = new LoginIdlingResource();
        onView(withId(R.id.fragment_login_button)).perform(click());
        
        Espresso.registerIdlingResources(loginIdlingResource);
        onView(withId(R.id.fab_footer)).check(matches(isDisplayed()));
        Espresso.unregisterIdlingResources(loginIdlingResource);
    }
}