Make workspace_layout handle all cons at workspace level, not only the first one (+test)

This makes opening new windows on workspace level and moving windows to the
right/left more like in the old i3.

testcases/t/67-workspace_layout.t

@@ -0,0 +1,139 @@
+#!perl
+# vim:ts=4:sw=4:expandtab
+# !NO_I3_INSTANCE! will prevent complete-run.pl from starting i3
+#
+# Tests the workspace_layout config option.
+#
+
+use i3test;
+use Cwd qw(abs_path);
+use Proc::Background;
+use File::Temp qw(tempfile tempdir);
+use X11::XCB qw(:all);
+use X11::XCB::Connection;
+
+my $x = X11::XCB::Connection->new;
+
+# assuming we are run by complete-run.pl
+my $i3_path = abs_path("../i3");
+
+#####################################################################
+# 1: check that with an empty config, cons are place next to each
+# other and no split containers are created
+#####################################################################
+
+my ($fh, $tmpfile) = tempfile();
+say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
+say $fh "ipc-socket /tmp/nestedcons";
+close($fh);
+
+diag("Starting i3");
+my $i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
+my $process = Proc::Background->new($i3cmd);
+sleep 1;
+
+diag("pid = " . $process->pid);
+
+my $tmp = fresh_workspace;
+
+ok(@{get_ws_content($tmp)} == 0, 'no containers yet');
+
+my $first = open_standard_window($x);
+my $second = open_standard_window($x);
+
+is($x->input_focus, $second->id, 'second window focused');
+ok(@{get_ws_content($tmp)} == 2, 'two containers opened');
+isnt($content[0]->{layout}, 'stacked', 'layout not stacked');
+isnt($content[1]->{layout}, 'stacked', 'layout not stacked');
+
+exit_gracefully($process->pid);
+
+#####################################################################
+# 2: set workspace_layout stacked, check that when opening two cons,
+# they end up in a stacked con
+#####################################################################
+
+($fh, $tmpfile) = tempfile();
+say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
+say $fh "ipc-socket /tmp/nestedcons";
+say $fh "workspace_layout stacked";
+close($fh);
+
+diag("Starting i3");
+$i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
+$process = Proc::Background->new($i3cmd);
+sleep 1;
+
+diag("pid = " . $process->pid);
+
+$tmp = fresh_workspace;
+
+ok(@{get_ws_content($tmp)} == 0, 'no containers yet');
+
+$first = open_standard_window($x);
+$second = open_standard_window($x);
+
+is($x->input_focus, $second->id, 'second window focused');
+my @content = @{get_ws_content($tmp)};
+ok(@content == 1, 'one con at workspace level');
+is($content[0]->{layout}, 'stacked', 'layout stacked');
+
+#####################################################################
+# 3: level up, open two new cons, check that they end up in a stacked
+# con
+#####################################################################
+
+cmd 'level up';
+my $right_top = open_standard_window($x);
+my $right_bot = open_standard_window($x);
+
+@content = @{get_ws_content($tmp)};
+is(@content, 2, 'two cons at workspace level after level up');
+is($content[0]->{layout}, 'stacked', 'layout stacked');
+is($content[1]->{layout}, 'stacked', 'layout stacked');
+
+#####################################################################
+# 4: move one of the cons to the right, check that it will end up in
+# a stacked con
+#####################################################################
+
+cmd 'move right';
+
+@content = @{get_ws_content($tmp)};
+is(@content, 3, 'three cons at workspace level after move');
+is($content[0]->{layout}, 'stacked', 'layout stacked');
+is($content[1]->{layout}, 'stacked', 'layout stacked');
+is($content[2]->{layout}, 'stacked', 'layout stacked');
+
+#####################################################################
+# 5: move it to the left again, check that the stacked con is deleted
+#####################################################################
+
+cmd 'move left';
+
+@content = @{get_ws_content($tmp)};
+is(@content, 2, 'two cons at workspace level after moving back');
+is($content[0]->{layout}, 'stacked', 'layout stacked');
+is($content[1]->{layout}, 'stacked', 'layout stacked');
+
+#####################################################################
+# 6: move it to a different workspace, check that it ends up in a
+# stacked con
+#####################################################################
+
+my $otmp = get_unused_workspace;
+
+cmd "move workspace $otmp";
+
+@content = @{get_ws_content($tmp)};
+is(@content, 2, 'still two cons on this workspace');
+is($content[0]->{layout}, 'stacked', 'layout stacked');
+is($content[1]->{layout}, 'stacked', 'layout stacked');
+
+@content = @{get_ws_content($otmp)};
+is(@content, 1, 'one con on target workspace');
+is($content[0]->{layout}, 'stacked', 'layout stacked');
+
+exit_gracefully($process->pid);
+
+done_testing;