Boat visible can be...

boat.rb

class Boat < ActiveRecord::Base
  MAX_VISIBLES = 7
  MEDIA_RESOURCES = [:profile, :home].freeze
  MEDIA_DIR = Rails.root.join('public', 'media', 'boats').freeze
  MENU_ACTIONS = [
                   :inside_views,
                   :outside_views,
                   :virtual_tours,
                   :video,
                   :layouts,
                   :tech_specs,
                   :catalogue
                 ].freeze

  validates :name, presence: true, uniqueness: { case_sensitive: false }
  validate  :visible_slots_available_only_if_visible?

  has_many :tech_specs, order: 'position'

  def visible?
    self.visible
  end

  def number
    @number ||= nil

    if @number.nil? || self.name_changed?
      if self.name.nil?
        @number = ''
      else
        @number = self.name.split.first
      end
    end

    @number
  end

  def suffix
    @suffix ||= nil

    if @suffix.nil? || self.name_changed?
      if self.name.nil?
        @suffix = ''
      else
        @suffix = self.name.split.second
      end
    end

    @suffix
  end

  def full_name
    "AP #{self.name.titleize}"
  end

  def to_s
    self.name
  end

  def visible_slots_available_only_if_visible?
    return true unless self.visible
    
    visible_boats_amount = self.class::visibles.size
    result = visible_boats_amount < self.class::MAX_VISIBLES

    unless result
      self.errors.add(:visible_slots_available_only_if_visible?,
                      "There are already #{ visible_boats_amount } over #{ self.class::MAX_VISIBLES }")
    end

    result
  end

  def has_resource?(resource)
    unless self.class::MEDIA_RESOURCES.include?(resource.to_sym)
      raise "Resource #{ resource } not in valid media resources"
    end
    
    self.send("has_resource_#{ resource }?")
  end

  def has_resource_profile?
    File.exist?(self.class::MEDIA_DIR.join(self.to_s.parameterize, 'profile.png'))
  end

  def self.visibles
    where(visible: true)
  end
end

boat_spec.rb

require 'spec_helper'

describe Boat do

  context "visible" do
    it "are not more than #{ Boat::MAX_VISIBLES }" do
      boats = FactoryGirl.create_list(:boat, Boat::MAX_VISIBLES)
      expect { FactoryGirl.create(:boat) }.to raise_error(ActiveRecord::RecordInvalid)
    end

    it "is not" do
      boats = FactoryGirl.create_list(:boat, Boat::MAX_VISIBLES)
      boats[0].visible = false
      boats[0].save!
      Boat.visibles.size.should be < Boat::MAX_VISIBLES
    end

    it "can be if there are less than #{ Boat::MAX_VISIBLES } boats visible" do
      boats = FactoryGirl.create_list(:boat, Boat::MAX_VISIBLES)
      boats[0].visible = false
      boats[0].save!
      print "----- visibles: #{ Boat.visibles.size }"
      FactoryGirl.create(:boat).should be_valid # This is line 62
    end
  end
end

Errors.txt

Failures:

  1) Boat visible can be if there are less than 7 boats visible
     Screenshot: /mnt/hgfs/d_wamp_www/austin/austinparker_it/tmp/capybara/screenshot_2013-03-17-01-43-15.348.png
     Failure/Error: FactoryGirl.create(:boat).should be_valid
       expected #<Boat id: 8, name: "Jarrod", created_at: "2013-03-17 00:43:15", updated_at: "2013-03-17 00:43:15", visible: true, short_description: "Velit eligendi sint voluptatem temporibus est fugit...", description: "Cupiditate maiores voluptatem quibusdam. Inventore ..."> to be valid, but got errors: Visible slots available only if visible? There are already 7 over 7
     # ./spec/models/boat_spec.rb:62:in `block (3 levels) in <top (required)>'

Finished in 1.92 seconds
10 examples, 1 failure

Failed examples:

rspec ./spec/models/boat_spec.rb:57 # Boat visible can be if there are less than 7 boats visible

factories.rb

FactoryGirl.define do
  factory :tech_spec_name do
    sequence(:name) { |n| "#{ Faker::Lorem.word } #{ n }"}
  end

  factory :boat do
    name { Faker::Name.first_name }
    short_description { Faker::Lorem.paragraph(1) }
    description { Faker::Lorem.paragraph }
    visible { true }

    factory :boat_with_tech_specs do
      ignore do
        tech_specs_count 5
      end

      after(:create) do |boat, evaluator|
        FactoryGirl.create_list(:tech_spec, evaluator.tech_specs_count, boat: boat)
      end
    end
  end

  factory :tech_spec do
    boat { FactoryGirl.create(:boat) }
    tech_spec_name { FactoryGirl.create(:tech_spec_name) }
    value { Faker::Lorem.word }
  end
end