application tests

android/app/src/test/AndroidManifest.xml

 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    package="com.reactnativenavigation">
+          package="com.reactnativenavigation">
 
-    <application android:theme="@style/Theme.AppCompat.Light"></application>
+    <application
+        android:name=".mocks.TestApplication"
+        android:theme="@style/Theme.AppCompat.Light">
+    </application>
 </manifest>

android/app/src/test/java/com/reactnativenavigation/NavigationActivityTest.java

 
 import org.junit.Test;
 import org.robolectric.Robolectric;
+import org.robolectric.android.controller.ActivityController;
 
 import static org.assertj.core.api.Java6Assertions.assertThat;
 
 
 	@Test
 	public void reportsLifecycleEventsToDelegate() throws Exception {
+		ActivityController<NavigationActivity> activityController = Robolectric.buildActivity(NavigationActivity.class);
+		activityController.create();
 	}
 }

android/app/src/test/java/com/reactnativenavigation/NavigationApplicationTest.java

+package com.reactnativenavigation;
+
+import com.facebook.react.ReactApplication;
+
+import org.junit.Test;
+import org.robolectric.RuntimeEnvironment;
+
+import static org.assertj.core.api.Java6Assertions.assertThat;
+
+public class NavigationApplicationTest extends BaseTest {
+
+	@Test
+	public void reactApplication() throws Exception {
+		assertThat(RuntimeEnvironment.application).isInstanceOf(ReactApplication.class);
+		assertThat(((ReactApplication) RuntimeEnvironment.application).getReactNativeHost()).isNotNull();
+	}
+
+	@Test
+	public void isDebug() throws Exception {
+		assertThat(((NavigationApplication) RuntimeEnvironment.application).isDebug()).isTrue();
+	}
+
+	@Test
+	public void singleInstance() throws Exception {
+		assertThat(RuntimeEnvironment.application).isSameAs(NavigationApplication.instance);
+	}
+}

android/app/src/test/java/com/reactnativenavigation/mocks/TestApplication.java

+package com.reactnativenavigation.mocks;
+
+import com.reactnativenavigation.BuildConfig;
+import com.reactnativenavigation.NavigationApplication;
+
+public class TestApplication extends NavigationApplication {
+	@Override
+	public boolean isDebug() {
+		return BuildConfig.DEBUG;
+	}
+}