tmt: Add tests for composefs system-reinstall

Mostly generated by LLM with some tweaks by me

Do not remove /usr/lib/bootupd/updates even when going down the
systemd-boot installation path as we require the metadata for testing
system reinstall

Signed-off-by: Pragyan Poudyal <pragyanpoudyal41999@gmail.com>

Author: Johan-Liebert1

contrib/packaging/switch-to-sdboot

@@ -11,7 +11,6 @@ shift
 # Uninstall bootupd if present (we're switching to sd-boot managed differently)
 if rpm -q bootupd &>/dev/null; then
   rpm -e bootupd
-  rm -vrf /usr/lib/bootupd/updates
 fi
 
 # First install the unsigned systemd-boot RPM to get the package in place

tmt/plans/integration.fmf

@@ -292,4 +292,11 @@ execute:
     how: fmf
     test:
       - /tmt/tests/tests/test-46-etc-merge-conflict
+
+/plan-47-system-reinstall-composefs:
+  summary: Test system-reinstall with composefs backend and bootloader compatibility
+  discover:
+    how: fmf
+    test:
+      - /tmt/tests/tests/test-47-system-reinstall-composefs
 # END GENERATED PLANS

tmt/tests/booted/test-system-reinstall-composefs.nu

@@ -0,0 +1,167 @@
+# number: 47
+# tmt:
+#   summary: Test system-reinstall with composefs backend and bootloader compatibility
+#   duration: 60m
+#
+# Tests that system-reinstall-bootc works with composefs backend by running
+# `bootc install to-existing-root --composefs-backend` on the live root,
+# matching the invocation pattern of system-reinstall-bootc.
+#
+# Three scenarios across three reboot cycles:
+#
+# Reboot 0:
+#   Same bootloader: image supports the host's bootloader
+#   → that bootloader should be installed
+#
+# Reboot 1:
+#   Verify same-bootloader result, then:
+#   Bootloader mismatch: image lacks support for the host's bootloader
+#   → fallback bootloader should be installed
+#   (skipped for UKI boot type where switching bootloaders is unsafe)
+#
+# Reboot 2:
+#   Verify mismatch fallback result
+#
+use std assert
+use tap.nu
+
+if not (tap is_composefs) {
+    exit 0
+}
+
+let st = bootc status --json | from json
+
+# Run bootc install to-existing-root --composefs-backend via podman,
+# matching the system-reinstall-bootc invocation from podman.rs.
+# Key details tested by these flags:
+#   /:/target:rslave  — propagates boot automount (commit 3bf1acba)
+#   --composefs-backend — exercises composefs repo init fix (commit fa18de18)
+#   efivars read      — bootloader detection (commits fa18de18, 4cb1e63b)
+def run_reinstall [image: string] {
+    (podman run
+        --rm
+        --privileged
+        --pid=host
+        --user=root:root
+        -v /var/lib/containers:/var/lib/containers
+        -v /dev:/dev
+        --security-opt label=type:unconfined_t
+        -v /:/target:rslave
+        $image
+        bootc install to-existing-root
+            --acknowledge-destructive
+            --skip-fetch-check
+            --composefs-backend
+            --disable-selinux)
+}
+
+def first_boot [] {
+    tap begin "system-reinstall composefs + bootloader compatibility"
+
+    let bootloader = ($st.status.booted.composefs.bootloader | str downcase)
+    let boot_type = ($st.status.booted.composefs.bootType | str downcase)
+
+    # Persist host state for verification across reboots
+    $bootloader | save /var/host-bootloader
+    $boot_type | save /var/host-boot-type
+
+    print $"Host bootloader: ($bootloader), boot type: ($boot_type)"
+
+    bootc image copy-to-storage
+
+    # Build derived image preserving the same bootloader support as the host.
+    # make_uki_containerfile appends UKI sealing stages when running on UKI.
+    let containerfile = (tap make_uki_containerfile "
+        FROM localhost/bootc as base
+        RUN rm -rf /usr/lib/bootc/bound-images.d
+        RUN touch /usr/share/testing-reinstall-same-bl
+    ")
+
+    let td = mktemp -d
+    cd $td
+    $containerfile | save Dockerfile
+    podman build -t localhost/bootc-reinstall-same .
+
+    print "Running to-existing-root --composefs-backend (same bootloader)"
+    run_reinstall localhost/bootc-reinstall-same
+
+    tmt-reboot
+}
+
+def second_boot [] {
+    print "Verifying reinstall with same bootloader"
+
+    assert (tap is_composefs) "composefs should be active after reinstall"
+    assert ("/usr/share/testing-reinstall-same-bl" | path exists) "same-bootloader marker should exist"
+
+    let orig_bootloader = (open /var/host-bootloader | str trim)
+    let current_bootloader = ($st.status.booted.composefs.bootloader | str downcase)
+
+    print $"Original bootloader: ($orig_bootloader), Current: ($current_bootloader)"
+    assert equal $current_bootloader $orig_bootloader "bootloader should match host after same-bootloader reinstall"
+
+    # Build image that lacks the host's bootloader, forcing a fallback:
+    #   host=systemd-boot -> remove bootctl -> falls back to grub
+    #   host=grub/grub-cc -> remove bootupd -> falls back to systemd-boot
+    bootc image copy-to-storage
+
+    let containerfile = if $orig_bootloader == "systemd" {
+        print "Building image without systemd-boot support (removing bootctl)"
+        "
+            FROM localhost/bootc as base
+            RUN rpm -e systemd-boot-unsigned
+            RUN rm -f /usr/bin/bootctl
+            RUN rm -rf /usr/lib/bootc/bound-images.d
+            RUN dnf install -y bootupd
+            RUN touch /usr/share/testing-reinstall-mismatch
+        "
+    } else {
+        print "Building image without grub/bootupd support"
+        "
+            FROM localhost/bootc as base
+            RUN rpm -e bootupd
+            RUN rm -rf /usr/lib/bootc/bound-images.d
+            RUN dnf install -y systemd-boot-unsigned
+            RUN touch /usr/share/testing-reinstall-mismatch
+        "
+    }
+
+    let td = mktemp -d
+    cd $td
+    $containerfile | save Dockerfile
+    podman build -t localhost/bootc-reinstall-mismatch .
+
+    print "Running to-existing-root --composefs-backend (mismatched bootloader)"
+    run_reinstall localhost/bootc-reinstall-mismatch
+
+    tmt-reboot
+}
+
+def third_boot [] {
+    print "Verifying reinstall with mismatched bootloader"
+
+    assert (tap is_composefs) "composefs should be active after mismatch reinstall"
+    assert ("/usr/share/testing-reinstall-mismatch" | path exists) "mismatch marker should exist"
+
+    let orig_bootloader = (open /var/host-bootloader | str trim)
+    let current_bootloader = ($st.status.booted.composefs.bootloader | str downcase)
+
+    print $"Original host bootloader: ($orig_bootloader), Installed: ($current_bootloader)"
+
+    if $orig_bootloader == "systemd" {
+        assert equal $current_bootloader "grub" "should fall back to grub when image lacks systemd-boot"
+    } else {
+        assert equal $current_bootloader "systemd" "should fall back to systemd-boot when image lacks grub"
+    }
+
+    tap ok
+}
+
+def main [] {
+    match $env.TMT_REBOOT_COUNT? {
+        null | "0" => first_boot,
+        "1" => second_boot,
+        "2" => third_boot,
+        $o => { error make { msg: $"Invalid TMT_REBOOT_COUNT ($o)" } },
+    }
+}

tmt/tests/tests.fmf

@@ -183,3 +183,8 @@ check:
   summary: Verify etc merge conflicts are caught during upgrade, not finalization
   duration: 15m
   test: nu booted/test-etc-merge-conflict.nu
+
+/test-47-system-reinstall-composefs:
+  summary: Test system-reinstall with composefs backend and bootloader compatibility
+  duration: 60m
+  test: nu booted/test-system-reinstall-composefs.nu