Copy (Clone) autofac registration

In a test project i found performance gap when i use Autofac latest version. I have BaseTest class that is base class for all tests. In ctor i create Autofac ContainerBuilder object, register all types, etc.

Then - build container and use it for Service Locator.

The problem is - i could not make container static and initialize it only one (not once per each test), to save ton of time on scanning assemblies for registering types, etc.

My goal - create static ContainerBuilder (or Container) - where in static ctor BaseTest i will register all types and then in usual ctor will copy this instance (with all registration) to non static property and use it for ServiceLocator.

Why i need it - because, for example TestA change/add substitution or so TestB does knows anything about that substitution. So i need clean up all customization about registration after each test set.

Do you have any ideas about how to do it? I search a lot of info in autofac - as i understand no possible to copy or clone container. Also i could not make ContainerBuilder static and in usual ctor call Build() or Update , because it`s not allowed.

Thanks in advance.