1 files changed, 5 insertions, 0 deletions
diff --git a/lib/test/unit.rb b/lib/test/unit.rb
index 72d403417f..af67a7aabd 100644
--- a/lib/test/unit.rb
+++ b/lib/test/unit.rb
@@ -388,6 +388,11 @@ module Test
       end
 
       def _run_parallel suites, type, result
+        if @opts[:parallel] < 1
+          warn "Error: parameter of -j option should be greater than 0."
+          return
+        end
+
         begin
           # Require needed things for parallel running
           require 'thread'