Fix threading issue with GUI. #1443 #1444

t/threads.t

@@ -0,0 +1,39 @@
+use Test::More;
+use strict;
+use warnings;
+
+BEGIN {
+    use FindBin;
+    use lib "$FindBin::Bin/../lib";
+}
+
+use List::Util qw(first);
+use Slic3r;
+use Slic3r::Test;
+
+if (!$Slic3r::have_threads) {
+    plan skip_all => "this perl is not compiled with threads";
+}
+plan tests => 2;
+
+{
+    my $print = Slic3r::Test::init_print('20mm_cube');
+    {
+        my $thread = threads->create(sub { Slic3r::thread_cleanup(); return 1; });
+        ok $thread->join, "print survives thread spawning";
+    }
+}
+    
+{
+    my $thread = threads->create(sub {
+        # $print can't be inizialized outside the thread because Object->slice will
+        # modify it by removing meshes and popping layers
+        my $print = Slic3r::Test::init_print('20mm_cube');
+        Slic3r::Test::gcode($print);
+        Slic3r::thread_cleanup();
+        return 1;
+    });
+    ok $thread->join, "process print in a separate thread";
+}
+
+__END__