Treat stacking containers as if they are in vertical orientation, add testcase

testcases/t/31-stacking-order.t

@@ -0,0 +1,64 @@
+#!perl
+# vim:ts=4:sw=4:expandtab
+#
+# Check if stacking containers can be used independantly of
+# the split mode (horizontal/vertical) of the underlying
+# container.
+#
+use i3test tests => 7;
+use Time::HiRes qw(sleep);
+
+my $i3 = i3("/tmp/nestedcons");
+
+my $tmp = get_unused_workspace();
+$i3->command("workspace $tmp")->recv;
+
+ok(@{get_ws_content($tmp)} == 0, 'no containers yet');
+
+# Enforce vertical split mode
+$i3->command('split v')->recv;
+
+$i3->command('open')->recv;
+my ($nodes, $focus) = get_ws_content($tmp);
+my $first = $focus->[0];
+
+$i3->command('open')->recv;
+($nodes, $focus) = get_ws_content($tmp);
+my $second = $focus->[0];
+
+isnt($first, $second, 'two different containers opened');
+
+##############################################################
+# change mode to stacking and cycle through the containers
+##############################################################
+
+$i3->command('layout stacking')->recv;
+($nodes, $focus) = get_ws_content($tmp);
+is($focus->[0], $second, 'second container still focused');
+
+$i3->command('next v')->recv;
+($nodes, $focus) = get_ws_content($tmp);
+is($focus->[0], $first, 'first container focused');
+
+$i3->command('prev v')->recv;
+($nodes, $focus) = get_ws_content($tmp);
+is($focus->[0], $second, 'second container focused again');
+
+##############################################################
+# now change the orientation to horizontal and cycle
+##############################################################
+
+$i3->command('level up')->recv;
+$i3->command('split h')->recv;
+$i3->command('level down')->recv;
+
+$i3->command('next v')->recv;
+($nodes, $focus) = get_ws_content($tmp);
+is($focus->[0], $first, 'first container focused');
+
+$i3->command('prev v')->recv;
+($nodes, $focus) = get_ws_content($tmp);
+is($focus->[0], $second, 'second container focused again');
+
+
+diag( "Testing i3, Perl $], $^X" );