1 files changed, 9 insertions, 0 deletions
diff --git a/test/ruby/test_regexp.rb b/test/ruby/test_regexp.rb
index 35d20eeda6..679a013cf0 100644
--- a/test/ruby/test_regexp.rb
+++ b/test/ruby/test_regexp.rb
@@ -1344,6 +1344,15 @@ class TestRegexp < Test::Unit::TestCase
     end
   end
 
+  def test_invalid_group
+    assert_separately([], "#{<<-"begin;"}\n#{<<-'end;'}")
+    begin;
+      assert_raise_with_message(RegexpError, /invalid conditional pattern/) do
+        Regexp.new("((?(1)x|x|)x)+")
+      end
+    end;
+  end
+
   # This assertion is for porting x2() tests in testpy.py of Onigmo.
   def assert_match_at(re, str, positions, msg = nil)
     re = Regexp.new(re) unless re.is_a?(Regexp)