RUBY-265 semantics should == Hash#reject!

lib/bson/ordered_hash.rb

@@ -125,11 +125,11 @@ module BSON
       end
 
       def delete_if(&block)
-        self.each { |k,v|
+        self.each do |k,v|
           if yield k, v
             delete(k)
           end
-        }
+        end
       end
 
       def reject(&block)
@@ -139,7 +139,14 @@ module BSON
       end
 
       def reject!(&block)
-        delete_if(&block)
+        changed = false
+        self.each do |k,v|
+          if yield k, v
+            changed = true
+            delete(k)
+          end
+        end
+        changed ? self : nil
       end
 
       def clear

test/bson/ordered_hash_test.rb

@@ -189,7 +189,8 @@ class OrderedHashTest < Test::Unit::TestCase
 
   def test_reject_bang
     @oh.reject! { |k, v| k == 'z' }
-    assert !@ok.keys.include?('z')
+    assert !@oh.keys.include?('z')
+    assert_nil @oh.reject! { |k, v| k == 'z' }
   end
 
   def test_clone