QA:Testcase webui partitioning guided 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 webui-based installer. Currently, that means using the Workstation live image.
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 webui-based installer using any available means. Currently, that means using the Workstation live image and selecting "Install to Disk..." at the end of the initial setup process.
2. In Installation Method, select the Reinstall Fedora scenario
3. Complete the installation process, making sensible selections for all other installer options.
4. Boot the installed system.
5. When Gnome Initial Setup prompts for new account creation make sure to use the same user name as the previous user to allow seamlessly reusing the /home/youruser directory.
6. 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. Any partitions or subvolumes which weren't assigned any mountpoints shouldn't be mounted.
4. Your personal files on your /home partition must be intact.