diff --git a/lib/cmock_header_parser.rb b/lib/cmock_header_parser.rb
index d248a8b..bf99cba 100644
--- a/lib/cmock_header_parser.rb
+++ b/lib/cmock_header_parser.rb
@@ -364,9 +364,9 @@ class CMockHeaderParser
     if funcs.empty?
       case @when_no_prototypes
       when :error
-        raise 'ERROR: No function prototypes found by CMock in #{filename}'
+        raise "ERROR: No function prototypes found by CMock in #{filename}"
       when :warn
-        puts 'WARNING: No function prototypes found by CMock in #{filename}' unless @verbosity < 1
+        puts "WARNING: No function prototypes found by CMock in #{filename}" unless @verbosity < 1
       end
     end
     funcs