formtastic_test_full_spec.rb

# spec/commit_button_spec.rb
it 'should pass options given in :button_html to the button' do
  @new_post.stub!(:new_record?).and_return(false)
  semantic_form_for(@new_post) do |builder|
    concat(builder.commit_button('text', :button_html => {:class => 'my_class', :id => 'my_id'}))
  end
  output_buffer.should have_tag('li.commit input#my_id')
  output_buffer.should have_tag('li.commit input.my_class')
end