Fix Multibyte::Chars#upcase/downcase

lib/mail/multibyte/chars.rb

@@ -339,15 +339,15 @@ def limit(limit)
       # Example:
       #   'Laurent, où sont les tests ?'.mb_chars.upcase.to_s # => "LAURENT, OÙ SONT LES TESTS ?"
       def upcase
-        chars(Unicode.apply_mapping(@wrapped_string), :uppercase_mapping)
+        chars(Unicode.apply_mapping(@wrapped_string, :uppercase_mapping))
       end
 
       # Convert characters in the string to lowercase.
       #
       # Example:
       #   'VĚDA A VÝZKUM'.mb_chars.downcase.to_s # => "věda a výzkum"
       def downcase
-        chars(Unicode.apply_mapping(@wrapped_string), :lowercase_mapping)
+        chars(Unicode.apply_mapping(@wrapped_string, :lowercase_mapping))
       end
 
       # Converts the first character to uppercase and the remainder to lowercase.

spec/mail/multibyte_spec.rb

@@ -0,0 +1,17 @@
+# encoding: utf-8
+require 'spec_helper'
+
+describe "multibyte/chars" do
+  Chars = Mail::Multibyte::Chars
+
+  it "should upcase" do
+    chars = Chars.new('Laurent, où sont les tests ?')
+    chars.upcase.should == "LAURENT, OÙ SONT LES TESTS ?"
+  end
+
+  it "should downcase" do
+    chars = Chars.new('VĚDA A VÝZKUM')
+    chars.downcase.should == "věda a výzkum"
+  end
+end
+