context 'when no right answer was selected' do
      it 'returns "Please select a correct answer for all questions"' do
        allow(true_false).to receive(:txt).and_return('Text')
        questions = { '1' => { txt: 'question text', iscorrect: '0' }, '2' => { txt: 'question text', iscorrect: '0' } }
        expect(true_false.isvalid(questions)).to eq('Please select a correct answer for all questions')