to_float support for non String values

lib/oga/xpath/conversion.rb

@@ -63,11 +63,7 @@ module Oga
           value = value.text
         end
 
-        if value.is_a?(String)
-          value = Float(value) rescue Float::NAN
-        end
-
-        value
+        Float(value) rescue Float::NAN
       end
 
       # @return [TrueClass|FalseClass]

spec/oga/xpath/conversion_spec.rb

@@ -176,6 +176,12 @@ describe Oga::XPath::Conversion do
         described_class.to_float(node).should == 10.5
       end
     end
+
+    describe 'using a NilClass' do
+      it 'returns Float::NAN' do
+        described_class.to_float(nil).should be_nan
+      end
+    end
   end
 
   describe 'to_boolean' do