tests: add check for long kernel parameters support in zipl

tests/zipl-long-params/main.fmf

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+summary: zipl-long-params
+description: |
+    Check for long parameter line support in zipl
+link: https://issues.redhat.com/browse/RHEL-105492
+contact: Daniel Horák <dhorak@redhat.com>
+component:
+  - s390utils
+test: ./runtest.sh
+framework: beakerlib
+require:
+  - s390utils-core
+  - grubby
+duration: 5m
+enabled: true
+adjust:
+  - when: arch != s390x
+    enabled: false
+    because: This test applies only to s390x systems.

tests/zipl-long-params/runtest.sh

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+#!/bin/bash
+# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+#
+#   Description: Check for long parameter line support in zipl
+#   Author: Dan Horák <dhorak@redhat.com>
+#
+# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+#
+#   Copyright (c) 2025 Red Hat, Inc.
+#
+#   This program is free software: you can redistribute it and/or
+#   modify it under the terms of the GNU General Public License as
+#   published by the Free Software Foundation, either version 2 of
+#   the License, or (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be
+#   useful, but WITHOUT ANY WARRANTY; without even the implied
+#   warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+#   PURPOSE.  See the GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program. If not, see http://www.gnu.org/licenses/.
+#
+# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+# Include Beaker environment
+. /usr/share/beakerlib/beakerlib.sh || exit 1
+
+PACKAGE="s390utils-core"
+PARAMS=params.txt
+
+rlJournalStart
+if [ "$TMT_REBOOT_COUNT" -eq 0 ]; then
+    rlPhaseStartSetup
+        rlAssertRpm $PACKAGE
+    rlPhaseEnd
+
+    rlPhaseStartTest "Check if long kernel parameter line is supported"
+        # add additional parameters for the default kernel, 24x 46B = 1104B, over the original 896B limit
+        ( for i in `seq -w 0 23`; do echo -n " param$i=`uuidgen`"; done ) > $PARAMS
+        rlRun 'grubby --args="$(cat $PARAMS)" --update-kernel=DEFAULT'
+        rlRun "zipl -V"
+    rlPhaseEnd
+
+    rlRun "tmt-reboot" 0 "Reboot the machine"
+
+elif [ "$TMT_REBOOT_COUNT" -eq 1 ]; then
+    rlPhaseStartTest "Check if all parameters are present after reboot"
+        rlRun "grep -f $PARAMS /proc/cmdline"
+    rlPhaseEnd
+
+    rlPhaseStartCleanup
+    rlPhaseEnd
+fi
+rlJournalPrintText
+rlJournalEnd