Sha256: 73d9e861bacb403fd86aca2014505071a59b0869415957bc884d291008d2dd31
Contents?: true
Size: 701 Bytes
Versions: 9
Compression:
Stored size: 701 Bytes
Contents
require 'spec_helper'
module Alf
class Aggregator
describe Variance do
let(:rel){[
{:qty => 10},
{:qty => 20},
{:qty => 30},
{:qty => 40}
]}
let(:expected) {
vals = rel.map{|t| t[:qty]}
mean = vals.inject(:+) / vals.size.to_f
vals.collect{|v| (v - mean)**2 }.inject(:+) / vals.size.to_f
}
it 'should work when used standalone' do
Variance.new{ qty }.aggregate(rel).should eq(expected)
end
it 'should install factory methods' do
Aggregator.variance{ qty }.should be_a(Variance)
Aggregator.variance{ qty }.aggregate(rel).should eq(expected)
end
end
end
end
Version data entries
9 entries across 9 versions & 2 rubygems