In your debugger-side class, include a static method that creates a VisualizerDevelopmentHost object and calls its show method:
public static void TestShowVisualizer(object objectToVisualize)
{
VisualizerDevelopmentHost myHost = new VisualizerDevelopmentHost(objectToVisualize, typeof(DebuggerSide));
myHost.ShowVisualizer();
}
The parameters used to construct the host are the data object that will be shown in the visualizer (objectToVisualize) and the type of the debugger side class.