Always substitute _ with - in attributes

Author: Petr Chalupa

lib/htmless/abstract/abstract_tag.rb

@@ -118,7 +118,7 @@ def open(attributes = nil)
         # @param [#to_s] value
         def attribute(name, value)
           return __send__(name, value) if respond_to?(name)
-          @output << @_str_space << name.to_s << @_str_eql_quote << CGI.escapeHTML(value.to_s) << @_str_quote
+          @output << @_str_space << name.to_s.gsub('_', '-') << @_str_eql_quote << CGI.escapeHTML(value.to_s) << @_str_quote
           self
         end
 

spec/htmless_spec.rb

@@ -185,6 +185,7 @@ def id;
     end
 
     it "#data-secret" do
+      quick_render { div('a', data_secret: "I do not tell.") }.should == '<div data-secret="I do not tell.">a</div>'
       quick_render { div('a').data_secret("I do not tell.") }.should == '<div data-secret="I do not tell.">a</div>'
     end