Infer currency negative format from positive one.

When a locale file sets the format of the positive
currency value as '%n %u', the default negative
currency format should be '-%n %u'.

Cherry-picked from master (6724c8c8)

1 files changed, 7 insertions, 0 deletions

diff --git a/actionpack/test/template/number_helper_i18n_test.rb b/actionpack/test/template/number_helper_i18n_test.rb
index 5df09b4d3b..d6e9de9555 100644
--- a/actionpack/test/template/number_helper_i18n_test.rb
+++ b/actionpack/test/template/number_helper_i18n_test.rb
@@ -53,6 +53,13 @@ class NumberHelperTest < ActionView::TestCase
       assert_equal("-$10.00", number_to_currency(-10))
     end
   end
+  
+  def test_number_to_currency_without_currency_negative_format
+    clean_i18n do
+      I18n.backend.store_translations 'ts', :number => { :currency => { :format => { :unit => '@', :format => '%n %u' } } }
+      assert_equal("-10.00 @", number_to_currency(-10, :locale => 'ts'))
+    end
+  end
 
   def test_number_with_i18n_precision
     #Delimiter was set to ""