Espresso click menu item

I have a menu in the actionbar which I create through:

@Override
public boolean onCreateOptionsMenu(Menu menu) {

    menu.add(Menu.NONE, 98,Menu.NONE,R.string.filter).setIcon(R.drawable.ic_filter_list_white_48dp).setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
    menu.add(Menu.NONE, 99,Menu.NONE,R.string.add).setIcon(R.drawable.ic_add_white_48dp).setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);


    getMenuInflater().inflate(R.menu.menu_main, menu);

    return true;
}

and menu_main.xml looks like:

<menu xmlns:android="http://ift.tt/nIICcg"
    xmlns:app="http://ift.tt/GEGVYd"
    xmlns:tools="http://ift.tt/LrGmb4"
    tools:context=".MainActivity">
    <item
        android:id="@+id/action_settings"
        android:title="@string/action_settings"
        android:orderInCategory="100"
        app:showAsAction="never"
        android:icon="@drawable/ic_settings_white_48dp"/>
</menu>

When testing in Espresso I would like to click on the "add" icon (menuId 99). I tried

@Test
public void testAdd() {
openActionBarOverflowOrOptionsMenu(InstrumentationRegistry.getTargetContext());
    onView(withText(R.string.add)).perform(click());
}

but this fails with a NoMatchingViewException. ( The settings item, which is defined in the xml directly I can click with the same code. )