diff --git a/tasks/mrbgem_spec.rake b/tasks/mrbgem_spec.rake
--- a/tasks/mrbgem_spec.rake
+++ b/tasks/mrbgem_spec.rake
unless rbfiles.empty?
f.puts %Q[ mrb_load_irep(mrb, gem_mrblib_irep_#{funcname});]
f.puts %Q[ if (mrb->exc) {]
+ f.puts %Q[ mrb_print_backtrace(mrb);]
f.puts %Q[ mrb_p(mrb, mrb_obj_value(mrb->exc));]
f.puts %Q[ exit(EXIT_FAILURE);]
f.puts %Q[ }]