fontFamily attribute not working via textAppearance

Question

I have next style:

 <style name="Text.Light">
        <item name="android:fontFamily">@font/open_sans_light</item>
    </style>

If I set it to TextView in xml via textAppearance like android:textAppearance="@style/Text.Italic" in design time it shows italic font, but in runtime it doesn't affect. But, if use fontFamily directly in TextView like android:fontFamily="@font/open_sans_italic" it works perfect in both cases (design and runtime). What am I doing wrong? There is my font-family xml:

<?xml version="1.0" encoding="utf-8"?>
<font-family xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    tools:ignore="UnusedAttribute">

    <font
        android:font="@font/open_sans_regular"
        android:fontStyle="normal"
        android:fontWeight="400"
        app:font="@font/open_sans_regular"
        app:fontStyle="normal"
        app:fontWeight="400" />

    <font
        android:font="@font/open_sans_italic"
        android:fontStyle="italic"
        android:fontWeight="400"
        app:font="@font/open_sans_italic"
        app:fontStyle="italic"
        app:fontWeight="400" />
</font-family>

Answer 1

The problem was I choose textViewStyle in my AppTheme and there was fontFamily. According to post textAppearance has minimum priority and it can't override other styles which defined in theme or anywhere else.