test: Use bootc image copy-to-storage and add run_install helper

Replace the complex get_target_image function with a simpler approach:
use `bootc image copy-to-storage` to copy the booted image to local
container storage, then reference it as containers-storage:localhost/bootc.

Also add a run_install helper in tap.nu to eliminate copy-pasted
systemd-run boilerplate across install tests.

Signed-off-by: Xiaofeng Wang <henrywangxf@me.com>

Author: henrywang

tmt/tests/booted/tap.nu

@@ -19,61 +19,15 @@ export def is_composefs [] {
     $st.status.booted.composefs? != null
 }
 
-# Get the target image for install tests based on the running OS
-# This ensures the target image matches the host OS to avoid version mismatches
-# (e.g., XFS features created by newer mkfs.xfs not recognized by older grub2)
-export def get_target_image [] {
-    # Parse os-release to get ID and VERSION_ID
-    let os = open /usr/lib/os-release
-        | lines
-        | filter {|l| $l != "" and not ($l | str starts-with "#") }
-        | parse "{key}={value}"
-        | reduce -f {} {|it, acc|
-            $acc | upsert $it.key ($it.value | str trim -c '"')
-        }
-
-    let id = $os.ID
-    let version_id = $os.VERSION_ID
-
-    # Construct the key for os-image-map.json
-    let key = if $id == "centos" {
-        # CentOS uses "centos-9" or "centos-10" format
-        $"centos-($version_id)"
-    } else if $id == "fedora" {
-        $"fedora-($version_id)"
-    } else if $id == "rhel" {
-        # RHEL uses "rhel-9.8" or "rhel-10.2" format
-        $"rhel-($version_id)"
-    } else {
-        # Fallback to centos-9 for unknown distros
-        "centos-9"
-    }
-
-    # Load the os-image-map.json - try multiple possible locations
-    let possible_paths = [
-        "hack/os-image-map.json",
-        "../../../hack/os-image-map.json",
-        "/var/home/bootc/hack/os-image-map.json"
-    ]
-
-    mut image_map = null
-    for p in $possible_paths {
-        if ($p | path exists) {
-            $image_map = (open $p)
-            break
-        }
-    }
-
-    # If map not found, use default centos-9 image
-    if ($image_map == null) {
-        return "docker://quay.io/centos-bootc/centos-bootc:stream9"
-    }
-
-    let image = $image_map.base | get -i $key
-    if ($image | is-empty) {
-        # Fallback to centos-9 if key not found
-        $"docker://($image_map.base.centos-9)"
-    } else {
-        $"docker://($image)"
-    }
+# Run a bootc install command in an isolated mount namespace.
+# This handles the common setup needed for install tests run outside a container.
+export def run_install [cmd: string] {
+    systemd-run -p MountFlags=slave -qdPG -- /bin/sh -c $"
+set -xeuo pipefail
+bootc usr-overlay
+if test -d /sysroot/ostree; then mount --bind /usr/share/empty /sysroot/ostree; fi
+rm -vrf /usr/lib/bootupd/updates
+rm -vrf /usr/lib/bootc/bound-images.d
+($cmd)
+"
 }

tmt/tests/booted/test-install-bootloader-none.nu

@@ -6,24 +6,18 @@
 use std assert
 use tap.nu
 
-let target_image = (tap get_target_image)
-
 def main [] {
     tap begin "install with --bootloader=none"
 
+    # Copy the booted image to container storage for use as install source
+    bootc image copy-to-storage
+    let target_image = "containers-storage:localhost/bootc"
+
     truncate -s 10G disk.img
 
     setenforce 0
 
-    systemd-run -p MountFlags=slave -qdPG -- /bin/sh -c $"
-set -xeuo pipefail
-bootc usr-overlay
-if test -d /sysroot/ostree; then mount --bind /usr/share/empty /sysroot/ostree; fi
-rm -vrf /usr/lib/bootupd/updates
-rm -vrf /usr/lib/bootc/bound-images.d
-# Install with --bootloader=none - skips bootloader management
-bootc install to-disk --disable-selinux --via-loopback --filesystem xfs --bootloader=none --source-imgref ($target_image) ./disk.img
-"
+    tap run_install $"bootc install to-disk --disable-selinux --via-loopback --filesystem xfs --bootloader=none --source-imgref ($target_image) ./disk.img"
 
     rm -f disk.img
 

tmt/tests/booted/test-install-no-boot-dir.nu

@@ -6,27 +6,21 @@
 use std assert
 use tap.nu
 
-let target_image = (tap get_target_image)
-
 def main [] {
     tap begin "install to-filesystem without /boot"
 
+    # Copy the booted image to container storage for use as install source
+    bootc image copy-to-storage
+    let target_image = "containers-storage:localhost/bootc"
+
     mkdir /var/mnt
     truncate -s 10G disk.img
     mkfs.ext4 disk.img
     mount -o loop disk.img /var/mnt
 
     setenforce 0
 
-    systemd-run -p MountFlags=slave -qdPG -- /bin/sh -c $"
-set -xeuo pipefail
-bootc usr-overlay
-if test -d /sysroot/ostree; then mount --bind /usr/share/empty /sysroot/ostree; fi
-rm -vrf /usr/lib/bootupd/updates
-rm -vrf /usr/lib/bootc/bound-images.d
-# Install to filesystem without /boot - skips bootloader management
-bootc install to-filesystem --disable-selinux --bootloader=none --source-imgref ($target_image) /var/mnt
-"
+    tap run_install $"bootc install to-filesystem --disable-selinux --bootloader=none --source-imgref ($target_image) /var/mnt"
 
     umount /var/mnt
     rm -f disk.img

tmt/tests/booted/test-install-outside-container.nu

@@ -39,15 +39,6 @@ let install_cmd = if (tap is_composefs) {
     $"($base_args) --filesystem xfs ./disk.img"
 }
 
-systemd-run -p MountFlags=slave -qdPG -- /bin/sh -c $"
-set -xeuo pipefail
-bootc usr-overlay
-if test -d /sysroot/ostree; then mount --bind /usr/share/empty /sysroot/ostree; fi
-# Note we do keep the other bootupd state
-rm -vrf /usr/lib/bootupd/updates
-# Another bootc install bug, we should not look at this in outside-of-container flows
-rm -vrf /usr/lib/bootc/bound-images.d
-($install_cmd)
-"
+tap run_install $install_cmd
 
 tap ok

tmt/tests/booted/test-install-unified-flag.nu

@@ -26,19 +26,7 @@ def main [] {
     # Disable SELinux enforcement for the install (same as test-install-outside-container)
     setenforce 0
 
-    # Perform the install with unified storage flag
-    # We use systemd-run to handle mount namespace issues
-    systemd-run -p MountFlags=slave -qdPG -- /bin/sh -c $"
-set -xeuo pipefail
-bootc usr-overlay
-if test -d /sysroot/ostree; then mount --bind /usr/share/empty /sysroot/ostree; fi
-# Note we do keep the other bootupd state
-rm -vrf /usr/lib/bootupd/updates
-# Another bootc install bug, we should not look at this in outside-of-container flows
-rm -vrf /usr/lib/bootc/bound-images.d
-# Install with unified storage flag to loopback disk
-bootc install to-disk --disable-selinux --via-loopback --filesystem xfs --experimental-unified-storage --source-imgref ($target_image) ./disk.img
-"
+    tap run_install $"bootc install to-disk --disable-selinux --via-loopback --filesystem xfs --experimental-unified-storage --source-imgref ($target_image) ./disk.img"
 
     # Cleanup
     rm -f disk.img