public void SetStrokesToNull()
{
InkPresenter ink = new InkPresenter();
object strokes;
// check that ReadLocalValue returns a collection after setting it to null via the property accessor
ink.Strokes = null;
strokes = ink.ReadLocalValue(InkPresenter.StrokesProperty);
Assert.IsTrue(strokes is StrokeCollection, "ReadLocalValue after setting to null returns a collection");
// check that ReadLocalValue returns a collection after SetValue to null
ink.SetValue(InkPresenter.StrokesProperty, null);
strokes = ink.ReadLocalValue(InkPresenter.StrokesProperty);
Assert.IsTrue(strokes is StrokeCollection, "ReadLocalValue after SetValue(null) returns a collection");
}