raise ArgumentError when has_one association was provided

lib/simple_form/form_builder.rb

@@ -183,7 +183,7 @@ module SimpleForm
         when :belongs_to
           (reflection.respond_to?(:options) && reflection.options[:foreign_key]) || :"#{reflection.name}_id"
         when :has_one
-          raise ":has_one associations are not supported by f.association"
+          raise ArgumentError, ":has_one associations are not supported by f.association"
         else
           if options[:as] == :select
             html_options = options[:input_html] ||= {}

test/form_builder/association_test.rb

@@ -120,7 +120,7 @@ class AssociationTest < ActionView::TestCase
 
   # ASSOCIATIONS - has_*
   test 'builder does not allow has_one associations' do
-    assert_raise RuntimeError do
+    assert_raise ArgumentError do
       with_association_for @user, :first_company, :as => :radio_buttons
     end
   end