react must be mocked in the unit tests

android/app/src/main/java/com/reactnativenavigation/NavigationApplication.java

 package com.reactnativenavigation;
 
+import android.app.Activity;
 import android.app.Application;
+import android.os.Bundle;
 
 import com.facebook.react.ReactApplication;
 import com.facebook.react.ReactNativeHost;
+import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;
+import com.reactnativenavigation.controllers.ActivityLifecycleDelegate;
 import com.reactnativenavigation.react.NavigationReactNativeHost;
 
 public abstract class NavigationApplication extends Application implements ReactApplication {
 	public static NavigationApplication instance;
-	private ReactNativeHost host;
+
+	public static class Config {
+		public final ReactNativeHost reactNativeHost;
+		public final ActivityLifecycleDelegate activityLifecycleDelegate;
+
+		public Config(ReactNativeHost reactNativeHost, ActivityLifecycleDelegate activityLifecycleDelegate) {
+			this.reactNativeHost = reactNativeHost;
+			this.activityLifecycleDelegate = activityLifecycleDelegate;
+		}
+	}
+
+	private Config config;
 
 	@Override
 	public void onCreate() {
 		super.onCreate();
 		instance = this;
-		host = new NavigationReactNativeHost(this);
+
+		config = createConfig();
+
+		registerActivityLifecycleCallbacks(new ActivityLifecycleCallbacks() {
+			@Override
+			public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
+				config().activityLifecycleDelegate.onActivityCreated(activity);
+			}
+
+			@Override
+			public void onActivityStarted(Activity activity) {
+
+			}
+
+			@Override
+			public void onActivityResumed(Activity activity) {
+				config().activityLifecycleDelegate.onActivityResumed(activity, (DefaultHardwareBackBtnHandler) activity);
+			}
+
+			@Override
+			public void onActivityPaused(Activity activity) {
+				config().activityLifecycleDelegate.onActivityPaused(activity);
+			}
+
+			@Override
+			public void onActivityStopped(Activity activity) {
+
+			}
+
+			@Override
+			public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
+
+			}
+
+			@Override
+			public void onActivityDestroyed(Activity activity) {
+				config().activityLifecycleDelegate.onActivityDestroyed(activity);
+			}
+		});
 	}
 
 	@Override
 	public ReactNativeHost getReactNativeHost() {
-		return host;
+		return config().reactNativeHost;
 	}
 
 	public abstract boolean isDebug();
+
+	public Config config() {
+		return config;
+	}
+
+	/**
+	 * override this to inject your own configuration
+	 *
+	 * @return the Config
+	 */
+	protected Config createConfig() {
+		ReactNativeHost reactNativeHost = new NavigationReactNativeHost(this, isDebug());
+		ActivityLifecycleDelegate activityLifecycleDelegate = new ActivityLifecycleDelegate(reactNativeHost.getReactInstanceManager());
+		return new Config(reactNativeHost, activityLifecycleDelegate);
+	}
 }

android/app/src/main/java/com/reactnativenavigation/controllers/ActivityLifecycleDelegate.java

 
 public class ActivityLifecycleDelegate {
 
-	private final Activity activity;
-	private final DefaultHardwareBackBtnHandler backBtnHandler;
 	private final ReactInstanceManager reactInstanceManager;
 	private final AtomicBoolean appLaunchEmitted = new AtomicBoolean(false);
 
-	public ActivityLifecycleDelegate(Activity activity,
-	                                 DefaultHardwareBackBtnHandler backBtnHandler,
-	                                 ReactInstanceManager reactInstanceManager) {
-		this.activity = activity;
-		this.backBtnHandler = backBtnHandler;
+	public ActivityLifecycleDelegate(ReactInstanceManager reactInstanceManager) {
 		this.reactInstanceManager = reactInstanceManager;
 	}
 
-	public void onActivityCreated() {
+	public void onActivityCreated(Activity activity) {
 		appLaunchEmitted.set(false);
 	}
 
-	public void onActivityResumed() {
+	public void onActivityResumed(Activity activity, DefaultHardwareBackBtnHandler backBtnHandler) {
 		if (ReactDevPermission.shouldAskPermission()) {
 			ReactDevPermission.askPermission(activity);
 		} else {
 		}
 	}
 
-	public void onActivityPaused() {
+	public void onActivityPaused(Activity activity) {
 		if (reactInstanceManager.hasStartedCreatingInitialContext()) {
 			reactInstanceManager.onHostPause(activity);
 		}
 	}
 
-	public void onActivityDestroyed() {
+	public void onActivityDestroyed(Activity activity) {
 		if (reactInstanceManager.hasStartedCreatingInitialContext()) {
 			reactInstanceManager.onHostDestroy(activity);
 		}

android/app/src/main/java/com/reactnativenavigation/react/NavigationReactNativeHost.java

 package com.reactnativenavigation.react;
 
+import android.app.Application;
+
 import com.facebook.react.ReactNativeHost;
 import com.facebook.react.ReactPackage;
 import com.facebook.react.shell.MainReactPackage;
-import com.reactnativenavigation.NavigationApplication;
 
 import java.util.Arrays;
 import java.util.List;
 
 public class NavigationReactNativeHost extends ReactNativeHost {
-	public NavigationReactNativeHost(NavigationApplication application) {
+	private boolean isDebug;
+
+	public NavigationReactNativeHost(Application application, boolean isDebug) {
 		super(application);
+		this.isDebug = isDebug;
 	}
 
 	@Override
 	public boolean getUseDeveloperSupport() {
-		return NavigationApplication.instance.isDebug();
+		return isDebug;
 	}
 
 	@Override
 	protected List<ReactPackage> getPackages() {
-		return Arrays.asList(
+		return Arrays.<ReactPackage>asList(
 				new MainReactPackage(),
 				new NavigationPackage()
 		);

android/app/src/test/AndroidManifest.xml

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

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

 package com.reactnativenavigation;
 
 import com.facebook.react.ReactApplication;
+import com.reactnativenavigation.controllers.ActivityLifecycleDelegate;
 
 import org.junit.Test;
 import org.robolectric.RuntimeEnvironment;
 	}
 
 	@Test
-	public void singleInstance() throws Exception {
+	public void singleGlobalInstance() throws Exception {
 		assertThat(RuntimeEnvironment.application).isSameAs(NavigationApplication.instance);
 	}
+
+	@Test
+	public void providesConfiguration() throws Exception {
+		assertThat(NavigationApplication.instance.config()).isInstanceOf(NavigationApplication.Config.class);
+	}
+
+	@Test
+	public void configProvidesActivityLifecycleDelegate() throws Exception {
+		NavigationApplication.Config config = NavigationApplication.instance.config();
+		assertThat(config.activityLifecycleDelegate).isInstanceOf(ActivityLifecycleDelegate.class);
+	}
 }

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

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

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;
-	}
-}