spec/ruby/library/prime/integer/prime_division_spec.rb


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require_relative '../../../spec_helper'

ruby_version_is ""..."3.1" do
  require 'prime'

  describe "Integer#prime_division" do
    it "returns an array of a prime factor and a corresponding exponent" do
      (2*3*5*7*11*13*17).prime_division.should ==
        [[2,1], [3,1], [5,1], [7,1], [11,1], [13,1], [17,1]]
    end

    it "returns an empty array for 1" do
      1.prime_division.should == []
    end
    it "returns an empty array for -1" do
      -1.prime_division.should == [[-1, 1]]
    end
    it "raises ZeroDivisionError for 0" do
      -> { 0.prime_division }.should raise_error(ZeroDivisionError)
    end
  end
end