public void UnselectAll_Clears_SelectedIndex_And_SelectedItem()
{
var target = new TestSelector
{
Template = Template(),
Items = new[] { "Foo", "Bar", "Baz" },
SelectionMode = SelectionMode.Multiple,
SelectedIndex = 0,
};
target.ApplyTemplate();
target.Presenter.ApplyTemplate();
target.UnselectAll();
Assert.Equal(-1, target.SelectedIndex);
Assert.Equal(null, target.SelectedItem);
}