QA:Testcase partitioning blivet btrfs preserve home

Associated release criterion
This test case is associated with the Fedora_42_Beta_Release_Criteria#Custom_partitioning release criterion. If you are doing release validation testing, a failure of this test case may be a breach of that release criterion. If so, please file a bug and nominate it as blocking the appropriate milestone, using the blocker bug nomination page.

Description

This test case ensures that the data in the /home directory is retained and usable on a Btrfs layout after another Fedora is installed on the same partition.

Setup

1. Prepare a test system with a working, supported storage device of sufficient size for a Fedora install, and a Fedora installation medium that uses the GTK-based installer. Do not use Fedora Workstation live on Fedora 41+, as that uses the webui-based installer.
2. Install Fedora 41 or 42 from any Edition or Spin which uses Btrfs filesystem by default. Ensure a separate /home subvolume is created. If you are installing to at least 50 GB of free space, this will happen if you use Automatic storage configuration during disk partitioning; otherwise, you will have to use custom partitioning and ensure a separate /home subvolume is created.
3. On the installed system, create some distinct files and directories in your home directory or directly in /home.

How to test

1. Boot the GTK-based installer using any available means. Do not use Fedora Workstation live on Fedora 41+, as that uses the webui-based installer.
2. Proceed to the installer's main screen, making sensible choices, and enter the Installation Destination screen.
3. In Installation Destination, use Advanced Custom (Blivet-GUI) partitioning
4. On the disk drive containing the existing Fedora installation, make sure the existing partitions formerly used as /boot and /boot/efi (if applicable) are reformatted and the same mountpoints are again assigned to them. (Alternatively, you can create new partitions and leave the old ones intact and without mountpoints).
5. In the list of existing btrfs volumes, locate the home subvolume of the existing installation and set the /home mountpoint to it.
6. You can delete all the other btrfs subvolumes, or you can keep them intact, but without any mountpoints assigned.
   • This refers to the root subvolume, but you can also see some additional subvolumes present as well, like root/var/lib/machines or root/var/lib/portables.
7. Create a new root subvolume and set the / mountpoint to it.
   • If you already have a root subvolume, because you decided to not delete the old one, that's not a problem, just name the new one differently.
8. Complete the installation process, making sensible selections for all other installer options.
9. Boot the installed system.
10. After logging in, check that your home directory or /home contains the files you created on your previous system (check their contents as well).

Expected Results

1. The expected partition layout should be created on the target device(s).
2. The install process should complete successfully and the installed system should boot as expected.
3. The partitions and subvolumes which were assigned some mountpoints in the installer should be mounted, and the partitions and subvolumes which weren't assigned any mountpoints shouldn't be mounted.
4. Your personal files on your /home partition must be intact.