added spec and pagination class to emulate paginary for using with Redis returned arrays.

lib/gitlab/pagination_delegate.rb

+module Gitlab
+  class PaginationDelegate
+    DEFAULT_PER_PAGE = Kaminari.config.default_per_page
+    MAX_PER_PAGE = Kaminari.config.max_per_page
+
+    def initialize(page:, per_page:, count:, options: {})
+      @count = count
+      @options = { default_per_page: DEFAULT_PER_PAGE,
+                   max_per_page: MAX_PER_PAGE }.merge(options)
+
+      @page = sanitize_page(page)
+      @per_page = sanitize_per_page(per_page)
+    end
+
+    def total_count
+      @count
+    end
+
+    def total_pages
+      (total_count.to_f / @per_page).ceil
+    end
+
+    def next_page
+      current_page + 1 unless last_page?
+    end
+
+    def prev_page
+      return nil if first_page?
+
+      current_page - 1 unless first_page?
+    end
+
+    def current_page
+      @page
+    end
+
+    def limit_value
+      @per_page
+    end
+
+    def first_page?
+      current_page == 1
+    end
+
+    def last_page?
+      current_page >= total_pages
+    end
+
+    def offset
+      (current_page - 1) * limit_value
+    end
+
+    private
+
+    def sanitize_per_page(per_page)
+      return @options[:default_per_page] unless per_page && per_page > 0
+
+      per_page > @options[:max_per_page] ? @options[:max_per_page] : per_page
+    end
+
+    def sanitize_page(page)
+      return 1 unless page && page > 1
+
+      page > total_count ? total_count : page
+    end
+  end
+end

spec/lib/gitlab/pagination_delegate_spec.rb

+require 'spec_helper'
+
+describe Gitlab::PaginationDelegate, lib: true do
+  context 'no data' do
+    let(:delegate) { described_class.new(page: 1,
+                                         per_page: 10,
+                                         count: 0) }
+
+    it 'shows the correct total count' do
+      expect(delegate.total_count).to eq(0)
+    end
+
+    it 'shows the correct total pages' do
+      expect(delegate.total_pages).to eq(0)
+    end
+
+    it 'shows the correct next page' do
+      expect(delegate.next_page).to be_nil
+    end
+
+    it 'shows the correct previous page' do
+      expect(delegate.prev_page).to be_nil
+    end
+
+    it 'shows the correct current page' do
+      expect(delegate.current_page).to eq(1)
+    end
+
+    it 'shows the correct limit value' do
+      expect(delegate.limit_value).to eq(10)
+    end
+
+    it 'shows the correct first page' do
+      expect(delegate.first_page?).to be true
+    end
+
+    it 'shows the correct last page' do
+      expect(delegate.last_page?).to be true
+    end
+
+    it 'shows the correct offset' do
+      expect(delegate.offset).to eq(0)
+    end
+  end
+
+  context 'with data' do
+    let(:delegate) { described_class.new(page: 5,
+                                         per_page: 100,
+                                         count: 1000) }
+
+    it 'shows the correct total count' do
+      expect(delegate.total_count).to eq(1000)
+    end
+
+    it 'shows the correct total pages' do
+      expect(delegate.total_pages).to eq(10)
+    end
+
+    it 'shows the correct next page' do
+      expect(delegate.next_page).to eq(6)
+    end
+
+    it 'shows the correct previous page' do
+      expect(delegate.prev_page).to eq(4)
+    end
+
+    it 'shows the correct current page' do
+      expect(delegate.current_page).to eq(5)
+    end
+
+    it 'shows the correct limit value' do
+      expect(delegate.limit_value).to eq(100)
+    end
+
+    it 'shows the correct first page' do
+      expect(delegate.first_page?).to be false
+    end
+
+    it 'shows the correct last page' do
+      expect(delegate.last_page?).to be false
+    end
+
+    it 'shows the correct offset' do
+      expect(delegate.offset).to eq(400)
+    end
+  end
+
+  context 'last page' do
+    let(:delegate) { described_class.new(page: 10,
+                                         per_page: 100,
+                                         count: 1000) }
+
+    it 'shows the correct total count' do
+      expect(delegate.total_count).to eq(1000)
+    end
+
+    it 'shows the correct total pages' do
+      expect(delegate.total_pages).to eq(10)
+    end
+
+    it 'shows the correct next page' do
+      expect(delegate.next_page).to be_nil
+    end
+
+    it 'shows the correct previous page' do
+      expect(delegate.prev_page).to eq(9)
+    end
+
+    it 'shows the correct current page' do
+      expect(delegate.current_page).to eq(10)
+    end
+
+    it 'shows the correct limit value' do
+      expect(delegate.limit_value).to eq(100)
+    end
+
+    it 'shows the correct first page' do
+      expect(delegate.first_page?).to be false
+    end
+
+    it 'shows the correct last page' do
+      expect(delegate.last_page?).to be true
+    end
+
+    it 'shows the correct offset' do
+      expect(delegate.offset).to eq(900)
+    end
+  end
+
+  context 'limits and defaults' do
+    it 'has a maximum limit per page' do
+      expect(described_class.new(page: nil,
+                                 per_page: 1000,
+                                 count: 0).limit_value).to eq(described_class::MAX_PER_PAGE)
+    end
+
+    it 'has a default per page' do
+      expect(described_class.new(page: nil,
+                                 per_page: nil,
+                                 count: 0).limit_value).to eq(described_class::DEFAULT_PER_PAGE)
+    end
+
+    it 'has a maximum page' do
+      expect(described_class.new(page: 100,
+                                 per_page: 10,
+                                 count: 1).current_page).to eq(1)
+    end
+  end
+end