crystal-scatter/spec/crystal-scatter_spec.cr

require "./spec_helper"

describe Crystal::Scatter do

    it "add elements to RingGraphs" do
        rg = Crystal::Scatter::RingGraph.new 
        rg.add(UInt64.new(1),[0,0,0,0,0,0],"OSD0")
        rg.add(UInt64.new(1),[0,0,0,0,0,1],"OSD1")
        rg.add(UInt64.new(1),[0,0,0,0,1,0],"OSD2")
        rg.get_weight.should eq(3)
        rg.generate_ring(BigRational.new(1))
        rg[0][0][0][0][0][0].range_effector.not_nil!.[0].should eq(0)
        rg[0][0][0][0][1][0].range_effector.not_nil!.[1].should eq(UInt64::MAX)
    end

    it "slices data into multiple pods" do
        mr = Crystal::Scatter::MetaRing.new(3)
        mr.add Crystal::Scatter::Daemon.new(1,[0,0,0,0,0,0],"OSD0")
        mr.add [Crystal::Scatter::Daemon.new(1,[0,0,0,0,0,1],"OSD1"),Crystal::Scatter::Daemon.new(1,[0,0,0,0,0,2],"OSD2")]
        
        (1..1000).each do |numb|
            slices = mr.get_slices_for(numb.to_s) 
            set = Set(String).new
            slices.each do |sl|
                set<<sl.url
            end
            set.size.should eq(3)
        end
    end

    it "hashes data fast" do
        v = Crystal::Scatter::MetaRing.new(3)
        time = Time.now
        (1..100).each do |numb|
            v.hash(numb.to_s)
        end
        t = (Time.now - time)
        (t.milliseconds <= 1).should be_true
    end

    it "hashes data good" do
        v = Crystal::Scatter::MetaRing.new(3)
        hash_nb =1000000
        store = Hash(UInt64, Int32).new
        (1..hash_nb).each do |numb|
            h = v.hash(numb.to_s)
            nb=store.fetch(h,0)
            store[h]=nb+1
        end
        
        
        conflicts = hash_nb-store.size
        (conflicts <= 100).should be_true


        mod_array = Array(Int32).new(1000,0)
        slice_array = Array(Int32).new(1000,0)

        store.each_key do |key|
            key_mod = key%1000
            mod_array[key_mod]+=1

            key_slice = key/(UInt64::MAX/1000)
            slice_array[key_slice]+=1
        end

        good_mod = true
        good_slice = true

        mod_array.each do |v|
            good_mod&=(v > (hash_nb/1000*4/5))
        end

        slice_array.each do |v|
            good_slice&=(v > (hash_nb/1000*4/5))
        end

        good_mod.should be_true
        good_slice.should be_true
    end
end