Kill almost all mutants in Zero::Request:AcceptType

Killed 13 of 14 mutants. I will see later, how it's possible to kill the last
one.
I also fixed the return value of "preferred", if the in initialize given string
is empty. Fixed the default value here.

1 files changed, 3 insertions, 6 deletions

diff --git a/lib/zero/request/accept_type.rb b/lib/zero/request/accept_type.rb
index 918bf24..a8f5dc9 100644
--- a/lib/zero/request/accept_type.rb
+++ b/lib/zero/request/accept_type.rb
@@ -8,11 +8,8 @@ module Zero
 
       # create a new instance of AcceptType
       def initialize(string)
-        if string.nil?
-          @elements = []
-        else
-          @elements = parse_elements(string)
-        end
+        string = '*/*' if string.nil? or string.empty?
+        @elements = parse_elements(string)
       end
 
       # return the preferred type
@@ -30,7 +27,7 @@ module Zero
 
       # converts the accept string to a useable array
       # @param string the string containing media ranges and options
-      def parse_elements(string = '*/*')
+      def parse_elements(string)
         string.
           gsub(/\s/, '').
           split(MEDIA_TYPE_SEPERATOR).