So far, you have been testing the web app portion of Ionic. Most of the time, you will need to actually run the app on a physical device or at least an emulator to see how the app behaves and whether all native features work.
You will need to have the emulator installed. iOS emulator comes when you do
npm install -g ios-sim and the Android emulator comes with Android Studio. To test the app on a physical device, you must connect the device to your computer via a USB connection.
$ ionic platform add ios $ ionic build ios
Note that you need to do the
platform add before building the app. However, ...