[Fixes #RUBY-641]: BSON::OrderedHash should allow options extraction using Array#extract_options!

Author: k-rudy

lib/bson/ordered_hash.rb

@@ -33,6 +33,14 @@ def ==(other)
       end
     end
 
+    # Allows activesupport Array#extract_options! to extract options
+    # when they are instance of BSON::OrderedHash
+    #
+    # @return [true, false] true if options can be extracted
+    def extractable_options?
+      instance_of?(BSON::OrderedHash)
+    end
+
     # We only need the body of this class if the RUBY_VERSION is before 1.9
     if RUBY_VERSION < '1.9'
       attr_accessor :ordered_keys

test/bson/ordered_hash_test.rb

@@ -258,4 +258,16 @@ def test_dup
     assert_nil @oh['f']
     assert_equal ['c', 'a', 'z'], @oh.keys
   end
+
+  def test_extractable_options_for_ordered_hash
+    assert @oh.extractable_options?
+  end
+
+  # Extractable_options should not be enabled by default for
+  # classes inherited from BSON::OrderedHash
+  #
+  def test_extractable_options_for_ordered_hash_inherited_classes_is_false
+    oh_child_class = Class.new(BSON::OrderedHash)
+    assert_false oh_child_class.new.extractable_options?
+  end
 end