Send paths argument as an array rather than converting it internally

actionmailer/lib/action_mailer/base.rb

@@ -748,7 +748,7 @@ def collect_responses(headers) #:nodoc:
         templates_path = headers.delete(:template_path) || self.class.mailer_name
         templates_name = headers.delete(:template_name) || action_name
 
-        each_template(templates_path, templates_name) do |template|
+        each_template(Array(templates_path), templates_name) do |template|
           self.formats = template.formats
 
           responses << {
@@ -762,9 +762,9 @@ def collect_responses(headers) #:nodoc:
     end
 
     def each_template(paths, name, &block) #:nodoc:
-      templates = lookup_context.find_all(name, Array(paths))
+      templates = lookup_context.find_all(name, paths)
       if templates.empty?
-        raise ActionView::MissingTemplate.new([paths], name, [paths], false, 'mailer')
+        raise ActionView::MissingTemplate.new(paths, name, paths, false, 'mailer')
       else
         templates.uniq { |t| t.formats }.each(&block)
       end