Add unit test for airbrake-1781551925379466692
user
```ruby
require 'rails_helper'

describe 'Airbrake-1781551925379466692' do
	it 'can deal with comment is nil' do
		questionnaire = Questionnaire.new
		qs = VmQuestionResponse.new(questionnaire, 1, 2)
		@list_of_reviews = [Response.new(id: 1)]
		@list_of_rows = [VmQuestionResponseRow.new('', 1, 1, 5, 0)]
		answer = Answer.new(id: 1, question_id: 1, response_id: 1, comments: nil)
		expect(qs.get_number_of_comments_greater_than_10_words).to eq([])
	end
end```
assistant