1 files changed, 9 insertions, 0 deletions
diff --git a/test/ruby/test_regexp.rb b/test/ruby/test_regexp.rb
index 24ac731d8e..2b10620d6c 100644
--- a/test/ruby/test_regexp.rb
+++ b/test/ruby/test_regexp.rb
@@ -28,4 +28,13 @@ class TestRegexp < Test::Unit::TestCase
   def test_ruby_dev_31309
     assert_equal('Ruby', 'Ruby'.sub(/[^a-z]/i, '-'))
   end
+
+  def test_assert_normal_exit
+    # moved from knownbug.  It caused core.
+    Regexp.union("a", "a")
+  end
+
+  def test_to_s
+    assert_equal '(?-mix:\000)', Regexp.new("\0").to_s
+  end
 end