test-kernel-install: add a simple test that kernel-install copies the files

I opted to tweaking kernel-install to allow overriding config
(with $KERNEL_INSTALL_CONF_ROOT, $KERNEL_INSTALL_PLUGINS). An alternative
would be to build a test environment in test/. We can still do that,
but I think it's nice to have a simple test that is very quick and easy
to debug.

Invocation as installkernel is for #23681.

meson.build

@@ -3751,7 +3751,7 @@ executable(
         install : true,
         install_dir : rootlibexecdir)
 
-public_programs += custom_target(
+exe = custom_target(
         'kernel-install',
         input : kernel_install_in,
         output : 'kernel-install',
@@ -3759,6 +3759,13 @@ public_programs += custom_target(
         install : want_kernel_install,
         install_mode : 'rwxr-xr-x',
         install_dir : bindir)
+public_programs += exe
+
+if want_tests != 'false'
+        test('test-kernel-install',
+             test_kernel_install_sh,
+             args : [exe.full_path(), loaderentry_install])
+endif
 
 ############################################################
 

src/kernel-install/meson.build

@@ -1,10 +1,11 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 
 kernel_install_in = files('kernel-install.in')
+loaderentry_install = files('90-loaderentry.install')
 
 if want_kernel_install
         install_data('50-depmod.install',
-                     '90-loaderentry.install',
+                     loaderentry_install,
                      install_mode : 'rwxr-xr-x',
                      install_dir : kernelinstalldir)
 
@@ -16,4 +17,5 @@ if want_kernel_install
                                          mkdir_p.format(sysconfdir / 'kernel/install.d'))
         endif
 
+        test_kernel_install_sh = find_program('test-kernel-install.sh')
 endif

src/kernel-install/test-kernel-install.sh

@@ -0,0 +1,83 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: LGPL-2.1-or-later
+set -eu
+set -o pipefail
+
+kernel_install="${1:?}"
+plugin="${2:?}"
+
+D="$(mktemp --tmpdir --directory "test-kernel-install.XXXXXXXXXX")"
+
+# shellcheck disable=SC2064
+trap "rm -rf '$D'" EXIT INT QUIT PIPE
+mkdir -p "$D/boot"
+mkdir -p "$D/efi"
+mkdir -p "$D/sources"
+
+echo 'buzy image' >"$D/sources/linux"
+echo 'the initrd' >"$D/sources/initrd"
+echo 'the-token' >"$D/sources/entry-token"
+echo 'opt1 opt2' >"$D/sources/cmdline"
+
+cat >"$D/sources/install.conf" <<EOF
+layout=bls
+initrd_generator=none
+# those are overriden by envvars
+BOOT_ROOT="$D/badboot"
+MACHINE_ID=badbadbadbadbadbad6abadbadbadbad
+EOF
+
+export KERNEL_INSTALL_CONF_ROOT="$D/sources"
+export KERNEL_INSTALL_PLUGINS="$plugin"
+export BOOT_ROOT="$D/boot"
+export MACHINE_ID='3e0484f3634a418b8e6a39e8828b03e3'
+
+"$kernel_install" -v add 1.1.1 "$D/sources/linux" "$D/sources/initrd"
+
+entry="$BOOT_ROOT/loader/entries/the-token-1.1.1.conf"
+test -f "$entry"
+grep -qE '^title ' "$entry"
+grep -qE '^version +1.1.1' "$entry"
+grep -qE '^options +opt1 opt2' "$entry"
+grep -qE '^linux .*/the-token/1.1.1/linux' "$entry"
+grep -qE '^initrd .*/the-token/1.1.1/initrd' "$entry"
+
+grep -qE 'image' "$BOOT_ROOT/the-token/1.1.1/linux"
+grep -qE 'initrd' "$BOOT_ROOT/the-token/1.1.1/initrd"
+
+"$kernel_install" inspect
+
+"$kernel_install" -v remove 1.1.1
+test ! -f "$entry"
+test ! -f "$BOOT_ROOT/the-token/1.1.1/linux"
+test ! -f "$BOOT_ROOT/the-token/1.1.1/initrd"
+
+# Invoke kernel-install as installkernel
+ln -s --relative -v "$kernel_install" "$D/sources/installkernel"
+"$D/sources/installkernel" -v 1.1.2 "$D/sources/linux" System.map /somedirignored
+
+entry="$BOOT_ROOT/loader/entries/the-token-1.1.2.conf"
+test -f "$entry"
+grep -qE '^title ' "$entry"
+grep -qE '^version +1.1.2' "$entry"
+grep -qE '^options +opt1 opt2' "$entry"
+grep -qE '^linux .*/the-token/1.1.2/linux' "$entry"
+( ! grep -qE '^initrd' "$entry" )
+
+grep -qE 'image' "$BOOT_ROOT/the-token/1.1.2/linux"
+test ! -e "$BOOT_ROOT/the-token/1.1.2/initrd"
+
+# Check installation with boot counting
+echo '56' >"$D/sources/tries"
+
+"$kernel_install" -v add 1.1.1 "$D/sources/linux" "$D/sources/initrd"
+entry="$BOOT_ROOT/loader/entries/the-token-1.1.1+56.conf"
+test -f "$entry"
+grep -qE '^title ' "$entry"
+grep -qE '^version +1.1.1' "$entry"
+grep -qE '^options +opt1 opt2' "$entry"
+grep -qE '^linux .*/the-token/1.1.1/linux' "$entry"
+grep -qE '^initrd .*/the-token/1.1.1/initrd' "$entry"
+
+grep -qE 'image' "$BOOT_ROOT/the-token/1.1.1/linux"
+grep -qE 'initrd' "$BOOT_ROOT/the-token/1.1.1/initrd"