test: import hostnamed tests from debian/ubuntu test suite

test/TEST-71-HOSTNAME/Makefile

@@ -0,0 +1 @@
+../TEST-01-BASIC/Makefile

test/TEST-71-HOSTNAME/test.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: LGPL-2.1-or-later
+set -e
+
+TEST_DESCRIPTION="test hostnamed"
+
+# shellcheck source=test/test-functions
+. "${TEST_BASE_DIR:?}/test-functions"
+
+do_test "$@"

test/units/testsuite-71.service

@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+[Unit]
+Description=TEST-71-HOSTNAME
+
+[Service]
+ExecStartPre=rm -f /failed /testok
+ExecStart=/usr/lib/systemd/tests/testdata/units/%N.sh
+StandardOutput=journal+console
+StandardError=journal+console
+Type=oneshot

test/units/testsuite-71.sh

@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+set -eux
+set -o pipefail
+
+# shellcheck source=test/units/assert.sh
+. "$(dirname "$0")"/assert.sh
+
+restore_hostname() {
+    if [[ -e /tmp/hostname.bak ]]; then
+        mv /tmp/hostname.bak /etc/hostname
+    else
+        rm -f /etc/hostname
+    fi
+}
+
+test_hostname() {
+    local orig=
+
+    if [[ -f /etc/hostname ]]; then
+        cp /etc/hostname /tmp/hostname.bak
+        orig=$(cat /etc/hostname)
+    fi
+
+    trap restore_hostname RETURN
+
+    # should activate daemon and work
+    if [[ -n "$orig" ]]; then
+        assert_in "Static hostname: $orig" "$(hostnamectl)"
+    fi
+    assert_in "Kernel: $(uname -s) $(uname -r)" "$(hostnamectl)"
+
+    # change hostname
+    assert_rc 0 hostnamectl set-hostname testhost
+    assert_eq "$(cat /etc/hostname)" "testhost"
+    assert_in "Static hostname: testhost" "$(hostnamectl)"
+
+    if [[ -n "$orig" ]]; then
+        # reset to original
+        assert_rc 0 hostnamectl set-hostname "$orig"
+        assert_eq "$(cat /etc/hostname)" "$orig"
+        assert_in "Static hostname: $orig" "$(hostnamectl)"
+    fi
+}
+
+: >/failed
+
+test_hostname
+
+touch /testok
+rm /failed