Merge pull request #462 from bovi/test-for-460

Add Test Case for Issue #460

test/t/string.rb

@@ -335,3 +335,7 @@ assert('String interpolation (mrb_str_concat for shared strings)') do
   "#{a}:" == "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA:"
 end
 
+assert('Check the usage of a NUL character') do
+  "qqq\0ppp"
+end
+