Updated the MainActivityTest

Author: florina-muntenescu

BasicSample/app/src/androidTest/java/com/example/android/persistence/ui/MainActivityTest.java

@@ -17,30 +17,39 @@
 package com.example.android.persistence.ui;
 
 
+import static android.support.test.espresso.Espresso.onView;
+import static android.support.test.espresso.action.ViewActions.click;
+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.withContentDescription;
+import static android.support.test.espresso.matcher.ViewMatchers.withText;
+
+import static org.hamcrest.core.IsNot.not;
+
 import android.arch.core.executor.testing.CountingTaskExecutorRule;
+import android.arch.lifecycle.LiveData;
+import android.arch.lifecycle.Observer;
+import android.support.annotation.Nullable;
+import android.support.test.InstrumentationRegistry;
 import android.support.test.espresso.contrib.RecyclerViewActions;
 import android.support.test.espresso.matcher.ViewMatchers;
 import android.support.test.rule.ActivityTestRule;
 
+import com.example.android.persistence.AppExecutors;
+import com.example.android.persistence.EspressoTestUtil;
+import com.example.android.persistence.R;
+import com.example.android.persistence.db.AppDatabase;
+
+import org.hamcrest.CoreMatchers;
+import org.hamcrest.MatcherAssert;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 
+import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 
-import static android.support.test.espresso.Espresso.onView;
-import static android.support.test.espresso.action.ViewActions.click;
-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.withContentDescription;
-import static android.support.test.espresso.matcher.ViewMatchers.withText;
-import static org.hamcrest.core.IsNot.not;
-
-import com.example.android.persistence.EspressoTestUtil;
-import com.example.android.persistence.R;
-import com.example.android.persistence.ui.MainActivity;
-
 public class MainActivityTest {
 
     @Rule
@@ -50,13 +59,43 @@ public class MainActivityTest {
     @Rule
     public CountingTaskExecutorRule mCountingTaskExecutorRule = new CountingTaskExecutorRule();
 
+    public MainActivityTest() {
+        // delete the database
+        InstrumentationRegistry.getTargetContext().deleteDatabase(AppDatabase.DATABASE_NAME);
+    }
+
     @Before
     public void disableRecyclerViewAnimations() {
+        // Disable RecyclerView animations
         EspressoTestUtil.disableAnimations(mActivityRule);
     }
 
+    @Before
+    public void waitForDbCreation() throws Throwable {
+        final CountDownLatch latch = new CountDownLatch(1);
+        final LiveData<Boolean> databaseCreated = AppDatabase.getInstance(
+                InstrumentationRegistry.getTargetContext(), new AppExecutors())
+                .getDatabaseCreated();
+        mActivityRule.runOnUiThread(new Runnable() {
+            @Override
+            public void run() {
+                databaseCreated.observeForever(new Observer<Boolean>() {
+                    @Override
+                    public void onChanged(@Nullable Boolean aBoolean) {
+                        if (Boolean.TRUE.equals(aBoolean)) {
+                            databaseCreated.removeObserver(this);
+                            latch.countDown();
+                        }
+                    }
+                });
+            }
+        });
+        MatcherAssert.assertThat("database should've initialized",
+                latch.await(1, TimeUnit.MINUTES), CoreMatchers.is(true));
+    }
+
     @Test
-    public void clickOnFirstItem_opensComments() throws TimeoutException, InterruptedException {
+    public void clickOnFirstItem_opensComments() throws Throwable {
         drain();
         // When clicking on the first product
         onView(ViewMatchers.withContentDescription(R.string.cd_products_list))

BasicSample/app/src/main/java/com/example/android/persistence/db/AppDatabase.java

@@ -25,6 +25,7 @@
 import android.arch.persistence.room.TypeConverters;
 import android.content.Context;
 import android.support.annotation.NonNull;
+import android.support.annotation.VisibleForTesting;
 
 import com.example.android.persistence.AppExecutors;
 import com.example.android.persistence.db.converter.DateConverter;
@@ -41,7 +42,8 @@ public abstract class AppDatabase extends RoomDatabase {
 
     private static AppDatabase sInstance;
 
-    private static final String DATABASE_NAME = "basic-sample-db";
+    @VisibleForTesting
+    public static final String DATABASE_NAME = "basic-sample-db";
 
     public abstract ProductDao productDao();
 

BasicSample/app/src/main/java/com/example/android/persistence/ui/MainActivity.java

@@ -18,9 +18,6 @@
 
 import android.os.Bundle;
 import android.support.annotation.Nullable;
-
-import android.arch.lifecycle.LifecycleActivity;
-import android.support.v4.app.FragmentActivity;
 import android.support.v7.app.AppCompatActivity;
 
 import com.example.android.persistence.R;

BasicSample/app/src/main/java/com/example/android/persistence/ui/ProductListFragment.java

@@ -17,7 +17,6 @@
 package com.example.android.persistence.ui;
 
 import android.arch.lifecycle.Lifecycle;
-import android.arch.lifecycle.LifecycleFragment;
 import android.arch.lifecycle.Observer;
 import android.arch.lifecycle.ViewModelProviders;
 import android.databinding.DataBindingUtil;