more fixes/tests for empty strings

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@9083 626c5289-ae23-0410-ae9c-e8d60b6d4f22

SWIG/Examples/test-suite/ruby/li_std_string_runme.rb

@@ -111,3 +111,23 @@ s = test_reference_inout("hello")
 if (s != "hellohello")
   raise RuntimeError
 end
+
+
+if (empty() != "")
+  raise RuntimeError
+end
+
+if (c_empty() != "") 
+  raise RuntimeError
+end
+
+
+if (c_null() != nil) 
+  raise RuntimeError
+end
+
+
+if (get_null(c_null()) != nil) 
+  raise RuntimeError
+end
+