Capybara, using expect inside within

I am working with Capybara right now and I have a issue I was not able to resolve: I am logging into a page and I want to check, whether the login was successful. So I have the following code:

    within(:id,'user_dropdown') do
        expect(find('.name')).to have_content 'test'
    end

But with doing this, I get the following error:

undefined method `expect' for #<Object:0x007fc39328ab78>

I think it has something to do, that expect is not available in the scope inside within. But how can I do this else?

Already thank you!