public void Should_return_all_plugins_of_the_specified_type()
{
var plugin1 = Plugin <IPluginType> .Create(new Plugin1());
var plugin2 = Plugin <IPluginType> .Create(new Plugin1());
var plugin3 = Plugin <IPluginType> .Create <Plugin1>();
_plugins.Append(Plugin <IPluginType> .Create(new Plugin2()));
_plugins.Append(plugin1);
_plugins.Append(plugin2);
_plugins.Append(Plugin <IPluginType> .Create <Plugin3>());
_plugins.Append(plugin3);
_plugins.AllOfType(typeof(Plugin1)).ShouldOnlyContain(plugin1, plugin2, plugin3);
}