diy-pager-total-pages-openstruct.rb

require "minitest/autorun"
require "minitest/spec"
require "ostruct"

class Pager
  def initialize(rows:, rows_per_page:)
    @rows = rows
    @rows_per_page = rows_per_page
  end

  def total_pages
    (@rows.count/@rows_per_page.to_f).ceil
  end
end

describe Pager do
  describe "#total_pages" do
    it "rounds up to the next whole number" do
      rows = OpenStruct.new(count: 33)

      pager = Pager.new(rows: rows, rows_per_page: 10)

      assert_equal pager.total_pages, 4
    end

    it "returns 1 when there are less than rows_per_page" do
      rows = OpenStruct.new(count: 5)

      pager = Pager.new(rows: rows, rows_per_page: 10)

      assert_equal pager.total_pages, 1
    end

    it "returns 0 when there are 0 rows" do
      rows = OpenStruct.new(count: 0)

      pager = Pager.new(rows: rows, rows_per_page: 10)

      assert_equal pager.total_pages, 0
    end
  end
end