Confused about Hyper-V checkpoints

Question

I use Hyper-V on windows 8.1 to set up test environments.

My checkpoint tree looks like this

Base
  +Test1
    >Now
  +Test2
  +Test3

Since these are test environments I normally don't want to keep changes when moving from one environment to another. i.e. I just Apply the checkpoint I want to move to.

The confusion appears when I want to keep changes in one environment. Lets say my tree looks like this:

Base
  +Test1
    >Now
  +Test2
    +Changes
  +Test3

My questions are:

• How do I merge the Changes checkpoint into Test2? Do I just Delete it?
• Lets say I don't need the Test3 environment anymore. How do I remove it? Will Delete merge it with Base

Currently I merge the changes like this but it seems too complicated:

1. Apply the Changes checkpoint

   Base
     +Test1
     +Test2
       +Changes
         >Now
     +Test3
   

2. Delete Checkpoint Subtree on Test2

   Base
     >Now
     +Test1
     +Test3
   

3. Create a new checkpoint and rename it Test2

   Base
     +Test2
       >Now
     +Test1
     +Test3
   

I always create and Apply checkpoints when the VM is shut down. Delete and Apply refers to the context menu choices.

Solution

I found this article and now I understand it.

The important point for my understanding is that checkpoints are always merged downstream (parent is merged into child).

If there are no checkpoints downstream (Now is considered a checkpoint in this context), the checkpoint is just deleted without merge.

What confused me was that differential disks, and undo-disks in Virtual PC, merge upstream (child is merged into parent).

So the answer to my questions above are:

• How do I merge the Changes checkpoint into Test2?

Not possible since you can't merge upstream!
What is possible is to merge Test2 into Changes by Deleting Test2!.

Base
  +Test1
    >Now
  +Changes
  +Test3

• Lets say I don't need the Test3 environment anymore. How do I remove it?

Test3 don't have any downstream checkpoints so it can just be Deleted If it has downstream checkpoints which should also be removed, use Delete Chekpoint subtree.