public void RegisterFactory_WithSingleton_Should_Return_OneInstance()
{
var resolver = new SimpleInjectorDependencyResolver();
resolver.RegisterFactory(typeof(Class6), () => new Class6(), LifetimeScope.Singleton);
var result = resolver.Resolve <Class6>();
var anotherResult = resolver.Resolve <Class6>();
Assert.IsNotNull(result);
Assert.AreEqual(result, anotherResult);
Assert.AreEqual(1, Class6.Instances);
}