set workspace_layout in create_workspace_on_output

fixes #835

src/workspace.c

@@ -212,6 +212,7 @@ Con *create_workspace_on_output(Output *output, Con *content) {
 
     ws->fullscreen_mode = CF_OUTPUT;
 
+    ws->workspace_layout = config.default_layout;
     _workspace_apply_default_orientation(ws);
 
     return ws;

testcases/t/509-workspace_layout.t

@@ -0,0 +1,43 @@
+#!perl
+# vim:ts=4:sw=4:expandtab
+#
+# Please read the following documents before working on tests:
+# • http://build.i3wm.org/docs/testsuite.html
+#   (or docs/testsuite)
+#
+# • http://build.i3wm.org/docs/lib-i3test.html
+#   (alternatively: perldoc ./testcases/lib/i3test.pm)
+#
+# • http://build.i3wm.org/docs/ipc.html
+#   (or docs/ipc)
+#
+# • http://onyxneon.com/books/modern_perl/modern_perl_a4.pdf
+#   (unless you are already familiar with Perl)
+#
+# Tests whether workspace_layout is properly set after startup.
+#
+use List::Util qw(first);
+use i3test i3_autostart => 0;
+
+my $config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+
+fake-outputs 1024x768+0+0
+workspace_layout tabbed
+EOT
+my $pid = launch_with_config($config);
+
+################################################################################
+# Test that workspace_layout is properly set
+################################################################################
+
+
+is(focused_ws, '1', 'starting on workspace 1');
+my $ws = get_ws(1);
+is($ws->{workspace_layout}, 'tabbed', 'workspace layout is "tabbed"');
+
+
+exit_gracefully($pid);
+
+done_testing;