public void Should_clear_all_plugins_except_specified_type()
{
_plugins.Append(Plugin <IPluginType> .Create <Plugin1>());
_plugins.Append(Plugin <IPluginType> .Create(new Plugin1()));
_plugins.Append(Plugin <IPluginType> .Create <Plugin2>());
_plugins.Count().ShouldEqual(3);
_plugins.ClearExcept <Plugin2>();
_plugins.Count().ShouldEqual(1);
_plugins.First().Type.ShouldEqual(typeof(Plugin2));
}