internal DrawingTest AssertIntersection(Point from, Point to, string intersected) { var context = getContext(); var navigator = new SceneNavigator(context.Items); var obstacle = navigator.GetFirstObstacle(from, to); if (obstacle == null) { Assert.IsNull(intersected, "Expected obstacle, but scene navigator hasn't detected any"); } Assert.AreEqual <DiagramItemDefinition>(obstacle.Definition, _items[intersected], "Incorrect intersection returned"); return(this); }