abstract ViewController

lib/android/app/src/main/java/com/reactnativenavigation/viewcontrollers/ViewController.java

 import android.support.annotation.Nullable;
 import android.view.View;
 
-public class ViewController {
+public abstract class ViewController {
 	private final Activity activity;
 	private final View view;
 	private StackController stackController;
 		this.view = onCreateView();
 	}
 
-	protected View onCreateView() {
-		return new View(getActivity());
-	}
+	protected abstract View onCreateView();
 
 	public boolean handleBack() {
 		return false;

lib/android/app/src/test/java/com/reactnativenavigation/mocks/SimpleViewController.java

+package com.reactnativenavigation.mocks;
+
+import android.app.Activity;
+import android.view.View;
+
+import com.reactnativenavigation.viewcontrollers.ViewController;
+
+public class SimpleViewController extends ViewController {
+	public SimpleViewController(final Activity activity) {
+		super(activity);
+	}
+
+	@Override
+	protected View onCreateView() {
+		return new View(getActivity());
+	}
+}

lib/android/app/src/test/java/com/reactnativenavigation/viewcontrollers/StackControllerTest.java

 import android.widget.FrameLayout;
 
 import com.reactnativenavigation.BaseTest;
+import com.reactnativenavigation.mocks.SimpleViewController;
 
 import org.junit.Ignore;
 import org.junit.Test;
 		super.beforeEach();
 		activity = newActivity();
 		uut = new StackController(activity);
-		child1 = new ViewController(activity);
-		child2 = new ViewController(activity);
-		child3 = new ViewController(activity);
+		child1 = new SimpleViewController(activity);
+		child2 = new SimpleViewController(activity);
+		child3 = new SimpleViewController(activity);
 	}
 
 	@Test

lib/android/app/src/test/java/com/reactnativenavigation/viewcontrollers/ViewControllerTest.java

 import android.view.View;
 
 import com.reactnativenavigation.BaseTest;
+import com.reactnativenavigation.mocks.SimpleViewController;
 
 import org.junit.Test;
 
 	public void beforeEach() {
 		super.beforeEach();
 		activity = newActivity();
-		uut = new ViewController(activity);
+		uut = new SimpleViewController(activity);
 	}
 
 	@Test