```ruby
require 'rails_helper'

RSpec.describe AmazonSidebar do
  describe 'without constructor parameters' do
    let(:sidebar) { AmazonSidebar.new }

    it "title should be 'Cited books'" do
      expect(sidebar.title).to eq('Cited books')
    end

    it "associate_id should be 'justasummary-20'" do
      expect(sidebar.associate_id).to eq('justasummary-20')
    end

    it 'maxlinks should be 4' do
      expect(sidebar.maxlinks).to eq(4)
    end

    it "description should be 'Adds sidebar links...'" do
      expect(sidebar.description).to eq(
        'Adds sidebar links to any Amazon.com books linked in the body of the page'
      )
    end

    it 'sidebar should be valid' do
      expect(sidebar).to be_valid
    end
  end

  describe 'with constructor parameters' do
    it 'gets attributes set correctly' do
      sb = AmazonSidebar.new(title: 'Books',
                             associate_id: 'justasummary-21',
                             maxlinks: 3)
      expect(sb).to be_valid
      expect(sb.title).to eq('Books')
      expect(sb.associate_id).to eq('justasummary-21')
      expect(sb.maxlinks).to eq(3)
    end
  end
end
```

Make specs pass with publify_core 9.0.0.pre5
user
```ruby
require 'rails_helper'

RSpec.describe AmazonSidebar do
  describe 'when using default values for its properties' do
    let(:sidebar) { AmazonSidebar.new(blog: Blog.new) }

    it "title should be 'Cited books'" do
      expect(sidebar.title).to eq('Cited books')
    end

    it "associate_id should be 'justasummary-20'" do
      expect(sidebar.associate_id).to eq('justasummary-20')
    end

    it 'maxlinks should be 4' do
      expect(sidebar.maxlinks).to eq(4)
    end

    it "description should be 'Adds sidebar links...'" do
      expect(sidebar.description).to eq(
        'Adds sidebar links to any Amazon.com books linked in the body of the page'
      )
    end

    it 'sidebar should be valid' do
      expect(sidebar).to be_valid
    end
  end

  describe 'when overriding the defaults' do
    it 'gets attributes set correctly' do
      sb = AmazonSidebar.new(title: 'Books',
                             associate_id: 'justasummary-21',
                             maxlinks: 3,
                             blog: Blog.new)
      expect(sb).to be_valid
      expect(sb.title).to eq('Books')
      expect(sb.associate_id).to eq('justasummary-21')
      expect(sb.maxlinks).to eq(3)
    end
  end
end
```
assistant