public void TestDraw(bool isEnabled)
        {
            var view     = new Mock <IStepper>();
            var canvas   = new Mock <ICanvas>();
            var drawable = new StepperDrawable(view.Object);

            drawable.IsEnabled = isEnabled;
            Assert.Equal(isEnabled, drawable.IsEnabled);

            var exception = Record.Exception(() =>
            {
                drawable.Draw(canvas.Object, new RectF(0, 0, 100, 100));
            });

            Assert.Null(exception);
        }