public void Injector_Should_Register_All_Singleton_Iterfaces()
{
// Arrange
var injector = new Injector();
injector.AllImplementationsSingleton <MultipleInterfacesClass>();
// Action
var first = injector.Get <ISample>();
var second = injector.Get <ICloneable>();
// Assert
first.Should().NotBeNull();
second.Should().NotBeNull();
first.Should().BeSameAs(second);
}