it 'instructor should be able to impersonate a teaching assistant user with their real name' do
      allow(User).to receive(:find_by).with(name: teaching_assistant.name).and_return(teaching_assistant)
      allow(instructor).to receive(:can_impersonate?).with(teaching_assistant).and_return(true)
      request.env['HTTP_REFERER'] = 'http://www.example.com'
      @params = { user: { name: teaching_assistant.name } }