Make testID work for iOS tabs

Reviewed By: shergin

Differential Revision: D6455054

fbshipit-source-id: 3c667b585e9332a1dbfff1fd3325f2c95985a5be

React/Views/RCTTabBarItem.h

@@ -28,6 +28,7 @@
 @property (nonatomic, assign, getter=isSelected) BOOL selected;
 @property (nonatomic, readonly) UITabBarItem *barItem;
 @property (nonatomic, copy) RCTBubblingEventBlock onPress;
+@property (nonatomic, strong) NSString *testID;
 
 #if TARGET_OS_TV
 @property (nonatomic, assign) BOOL wasSelectedInJS;

React/Views/RCTTabBarItem.m

@@ -58,6 +58,11 @@ RCT_ENUM_CONVERTER(UITabBarSystemItem, (@{
   return _barItem;
 }
 
+- (void)setTestID:(NSString *)testID
+{
+  self.barItem.accessibilityIdentifier = testID;
+}
+
 - (void)setBadge:(id)badge
 {
   _badge = [badge copy];

React/Views/RCTTabBarItemManager.m

@@ -30,6 +30,7 @@ RCT_EXPORT_VIEW_PROPERTY(systemIcon, UITabBarSystemItem)
 RCT_EXPORT_VIEW_PROPERTY(onPress, RCTBubblingEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(badgeColor, UIColor)
 RCT_EXPORT_VIEW_PROPERTY(isTVSelectable, BOOL)
+RCT_EXPORT_VIEW_PROPERTY(testID, NSString)
 RCT_CUSTOM_VIEW_PROPERTY(title, NSString, RCTTabBarItem)
 {
   view.barItem.title = json ? [RCTConvert NSString:json] : defaultView.barItem.title;