discourse/spec/lib/timeline_lookup_spec.rb

# frozen_string_literal: true

require 'rails_helper'

describe TimelineLookup do

  context '.build' do
    it 'keeps the last tuple in the lookup' do
      tuples = [
        [7173, 400], [7174, 390], [7175, 380], [7176, 370], [7177, 1]
      ]

      expect(TimelineLookup.build(tuples, 2)).to eq([[1, 400], [4, 370], [5, 1]])
    end
  end

end
FIX: ensures timeline_lookup includes last tuple (#11829) A simplified version of the logic used in the function before my fix is as follow: ```ruby result = [] things = [0,1,2,3] max_values = 2 every = (things.size.to_f / max_values).ceil things.each_with_index do \|t, index\| next unless (t % every) === 0 result << t end p result # [0, 2] # 3 doesn’t get included ``` The problem is that if you get unlucky two times you won't get last tuple(s) and might get a very erroneous date. Double unlucky: - last tuple index % computed every !== 0 and you don't get the last tuple - the last tuple is related to a post with a very different date than the previous tuples (on year difference in our case) 2021-01-25 04:30:59 -06:00			`# frozen_string_literal: true`

			`require 'rails_helper'`

			`describe TimelineLookup do`

			`context '.build' do`
			`it 'keeps the last tuple in the lookup' do`
			`tuples = [`
			`[7173, 400], [7174, 390], [7175, 380], [7176, 370], [7177, 1]`
			`]`

			`expect(TimelineLookup.build(tuples, 2)).to eq([[1, 400], [4, 370], [5, 1]])`
			`end`
			`end`

			`end`