test(netboot): cover volatile kernel arguments

xCAT-test/unit/boot_utils.t

@@ -0,0 +1,39 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+use FindBin;
+use lib "$FindBin::Bin/../../perl-xCAT";
+
+use Test::More;
+
+use xCAT::BootUtils;
+
+my @cases = (
+    [ undef, undef, 'undefined input remains undefined' ],
+    [ '', '', 'empty input remains empty' ],
+    [ '0', '0', 'false string input remains unchanged' ],
+    [ 'console=ttyS0 quiet', 'console=ttyS0 quiet ', 'volatile options are retained' ],
+    [ 'R::root=/dev/sda R::console=ttyS0', '', 'persistent-only options are omitted' ],
+    [
+        'console=ttyS0 R::root=/dev/sda quiet',
+        'console=ttyS0 quiet ',
+        'persistent options are omitted from mixed input'
+    ],
+    [
+        'first R::persist=1 second R::last=1 third',
+        'first second third ',
+        'volatile option ordering is preserved'
+    ],
+);
+
+for my $case (@cases) {
+    my ($input, $expected, $description) = @{$case};
+    is( xCAT::BootUtils::volatile_addkcmdline($input), $expected, $description );
+}
+
+my $original = 'first R::persist=1 second';
+is( xCAT::BootUtils::volatile_addkcmdline($original), 'first second ', 'the normalized value is returned' );
+is( $original, 'first R::persist=1 second', 'the caller value is not modified' );
+
+done_testing();