Merge child options when child appears

lib/android/app/src/main/java/com/reactnativenavigation/parse/Options.java

         topTabOptions.tabIndex = i;
     }
 
+    @CheckResult
+    public Options copy() {
+        return new Options().mergeWith(this);
+    }
+
     @CheckResult
 	public Options mergeWith(final Options other) {
         Options result = new Options();
         result.topBarOptions.mergeWith(other.topBarOptions);
         result.topTabsOptions.mergeWith(other.topTabsOptions);
+        result.topTabOptions.mergeWith(other.topTabOptions);
         result.bottomTabOptions.mergeWith(other.bottomTabOptions);
         result.bottomTabsOptions.mergeWith(other.bottomTabsOptions);
         return result;
 
     Options withDefaultOptions(final Options other) {
         topBarOptions.mergeWithDefault(other.topBarOptions);
+        topTabOptions.mergeWithDefault(other.topTabOptions);
         topTabsOptions.mergeWithDefault(other.topTabsOptions);
         bottomTabOptions.mergeWithDefault(other.bottomTabOptions);
         bottomTabsOptions.mergeWithDefault(other.bottomTabsOptions);

lib/android/app/src/main/java/com/reactnativenavigation/parse/TopTabOptions.java

         return result;
     }
 
-    void mergeWith(TopTabOptions topTabsOptions) {
-
+    void mergeWith(TopTabOptions other) {
+        if (other.title.hasValue()) title = other.title;
+        if (other.fontFamily != null) fontFamily = other.fontFamily;
+        if (other.tabIndex >= 0) tabIndex = other.tabIndex;
     }
 
-    void mergeWithDefault(TopTabOptions topTabsOptions) {
-
+    void mergeWithDefault(TopTabOptions other) {
+        if (fontFamily == null) fontFamily = other.fontFamily;
     }
 }

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

 
     @CallSuper
     public void applyOptions(Options options, ReactComponent childComponent) {
+        mergeChildOptions(options);
+        applyOnParentController(parentController -> ((ParentController) parentController).applyOptions(this.options, childComponent));
+    }
+
+    private void mergeChildOptions(Options options) {
         this.options = this.options.mergeWith(options);
     }
 

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

     public void applyOptions(Options options, ReactComponent component) {
         super.applyOptions(options, component);
         stackLayout.applyOptions(this.options, component);
-        applyOnParentController(parentController -> ((ParentController) parentController).applyOptions(this.options, component));
     }
 
     @Override

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

         boolean onViewDisappear(View view);
     }
 
+    Options initialOptions;
     public Options options;
 
     private final Activity activity;
     public ViewController(Activity activity, String id, Options initialOptions) {
         this.activity = activity;
         this.id = id;
-        options = initialOptions;
+        this.initialOptions = initialOptions;
+        options = initialOptions.copy();
     }
 
     protected abstract T createView();

lib/android/app/src/main/java/com/reactnativenavigation/viewcontrollers/toptabs/TopTabsController.java

     @Override
     public void applyOptions(Options options, ReactComponent childComponent) {
         super.applyOptions(options, childComponent);
-        applyOnParentController(parentController -> ((ParentController) parentController).applyOptions(this.options, childComponent));
     }
 
     @Override

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

 
     @Test
     public void initialOptionsAppliedOnAppear() throws Exception {
-        assertThat(uut.options).isSameAs(initialNavigationOptions);
-        initialNavigationOptions.topBarOptions.title = new Text("the title");
+        uut.options.topBarOptions.title = new Text("the title");
         StackController stackController = new StackController(activity, "stackId", new Options());
         stackController.animatePush(uut, new MockPromise() {});
         assertThat(stackController.getTopBar().getTitle()).isEmpty();
 
     @Test
     public void appliesTopBarTextColor() throws Exception {
-        assertThat(uut.options).isSameAs(initialNavigationOptions);
+        assertThat(uut.initialOptions).isSameAs(initialNavigationOptions);
         stackController.animatePush(uut, new MockPromise() {
             @Override
             public void resolve(@Nullable Object value) {
 
     @Test
     public void appliesTopBarTextSize() throws Exception {
-        assertThat(uut.options).isSameAs(initialNavigationOptions);
+        assertThat(uut.initialOptions).isSameAs(initialNavigationOptions);
         initialNavigationOptions.topBarOptions.title = new Text("the title");
         uut.ensureViewIsCreated();
         uut.onViewAppeared();
 
     @Test
     public void appliesTopBarHidden() throws Exception {
-        assertThat(uut.options).isSameAs(initialNavigationOptions);
+        assertThat(uut.initialOptions).isSameAs(initialNavigationOptions);
         initialNavigationOptions.topBarOptions.title = new Text("the title");
         uut.ensureViewIsCreated();
         uut.onViewAppeared();
 
     @Test
     public void appliesDrawUnder() throws Exception {
-        assertThat(uut.options).isSameAs(initialNavigationOptions);
-        initialNavigationOptions.topBarOptions.title = new Text("the title");
-        initialNavigationOptions.topBarOptions.drawBehind = Options.BooleanOptions.False;
+        uut.options.topBarOptions.title = new Text("the title");
+        uut.options.topBarOptions.drawBehind = Options.BooleanOptions.False;
         uut.ensureViewIsCreated();
         uut.onViewAppeared();
         stackController.animatePush(uut, new MockPromise() {

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

 package com.reactnativenavigation.viewcontrollers;
 
-import android.app.*;
-import android.support.annotation.*;
-import android.view.*;
-import android.widget.*;
-
-import com.reactnativenavigation.*;
-import com.reactnativenavigation.mocks.*;
+import android.app.Activity;
+import android.support.annotation.NonNull;
+import android.view.ViewGroup;
+import android.widget.FrameLayout;
+
+import com.reactnativenavigation.BaseTest;
+import com.reactnativenavigation.mocks.MockPromise;
+import com.reactnativenavigation.mocks.SimpleViewController;
 import com.reactnativenavigation.parse.Options;
+import com.reactnativenavigation.parse.Text;
+import com.reactnativenavigation.views.ReactComponent;
 
-import org.junit.*;
+import org.junit.Test;
+import org.mockito.ArgumentCaptor;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
 
-import static org.assertj.core.api.Java6Assertions.*;
-import static org.mockito.Mockito.*;
+import static org.assertj.core.api.Java6Assertions.assertThat;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
 
 public class ParentControllerTest extends BaseTest {
 
+    public static final String INITIAL_TITLE = "initial title";
     private Activity activity;
     private List<ViewController> children;
     private ParentController uut;
         super.beforeEach();
         activity = newActivity();
         children = new ArrayList<>();
-        uut = new ParentController(activity, "uut", new Options()) {
+        Options initialOptions = new Options();
+        initialOptions.topBarOptions.title = new Text(INITIAL_TITLE);
+        uut = spy(new ParentController(activity, "uut", initialOptions) {
 
             @NonNull
             @Override
             protected ViewGroup createView() {
-                return new FrameLayout(activity);
+                FrameLayout layout = new FrameLayout(activity);
+                for (ViewController child : children) {
+                    child.setParentController(this);
+                    layout.addView(child.getView());
+                }
+                return layout;
             }
 
             @NonNull
             public Collection<ViewController> getChildControllers() {
                 return children;
             }
-        };
+        });
     }
 
     @Test
         child1.onViewAppeared();
         verify(stackController, times(1)).clearOptions();
     }
+
+    @Test
+    public void mergeOptions_optionsAreMergedWhenChildAppears() throws Exception {
+        Options options = new Options();
+        options.topBarOptions.title = new Text("new title");
+        ViewController child1 = spy(new SimpleViewController(activity, "child1", options));
+        children.add(child1);
+        uut.ensureViewIsCreated();
+
+        child1.ensureViewIsCreated();
+        child1.onViewAppeared();
+        ArgumentCaptor<Options> optionsCaptor = ArgumentCaptor.forClass(Options.class);
+        ArgumentCaptor<ReactComponent> viewCaptor = ArgumentCaptor.forClass(ReactComponent.class);
+        verify(uut, times(1)).applyOptions(optionsCaptor.capture(), viewCaptor.capture());
+        assertThat(optionsCaptor.getValue().topBarOptions.title.get()).isEqualTo("new title");
+        assertThat(viewCaptor.getValue()).isEqualTo(child1.getView());
+    }
+
+    @Test
+    public void mergeOptions_initialParentOptionsAreNotMutatedWhenChildAppears() throws Exception {
+        Options options = new Options();
+        options.topBarOptions.title = new Text("new title");
+        ViewController child1 = spy(new SimpleViewController(activity, "child1", options));
+        children.add(child1);
+
+        uut.ensureViewIsCreated();
+
+        child1.ensureViewIsCreated();
+        child1.onViewAppeared();
+        assertThat(uut.initialOptions.topBarOptions.title.get()).isEqualTo(INITIAL_TITLE);
+    }
 }

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

 import com.reactnativenavigation.views.TopTabsLayoutCreator;
 import com.reactnativenavigation.views.TopTabsViewPager;
 
+import org.assertj.core.api.Assertions;
 import org.junit.Test;
 import org.mockito.Mockito;
 
         for (int i = 0; i < SIZE; i++) {
             final Options options = new Options();
             options.topTabOptions.title = new Text("Tab " + i);
-            options.topBarOptions.title = new Text("Title " + i);
+            options.topBarOptions.title = new Text(createTabTopBarTitle(i));
             result.add(options);
         }
         return result;
         tabControllers.get(1).ensureViewIsCreated();
 
         uut.onViewAppeared();
-        verify(uut, times(1)).applyOptions(tabOptions.get(0), tabView(0));
+        ReactComponent currentTab = tabView(0);
+        verify(uut, times(1)).applyOptions(any(Options.class), eq(currentTab));
+        Assertions.assertThat(uut.options.topBarOptions.title.get()).isEqualTo(createTabTopBarTitle(0));
+
         uut.switchToTab(1);
-        verify(uut, times(1)).applyOptions(tabOptions.get(1), tabView(1));
+        currentTab = tabView(1);
+        verify(uut, times(1)).applyOptions(any(Options.class), eq(currentTab));
+        Assertions.assertThat(uut.options.topBarOptions.title.get()).isEqualTo(createTabTopBarTitle(1));
+
         uut.switchToTab(0);
-        verify(uut, times(2)).applyOptions(tabOptions.get(0), tabView(0));
+        currentTab = tabView(0);
+        verify(uut, times(2)).applyOptions(any(Options.class), eq(currentTab));
+        Assertions.assertThat(uut.options.topBarOptions.title.get()).isEqualTo(createTabTopBarTitle(0));
     }
 
     private TestReactView getActualTabView(int index) {
     private IReactView tab(TopTabsViewPager topTabs, final int index) {
         return (IReactView) ((ViewGroup) topTabs.getChildAt(index)).getChildAt(0);
     }
+
+    private String createTabTopBarTitle(int i) {
+        return "Title " + i;
+    }
 }