Prime Finder RubyGames

prime_finder.rb

class PrimeFinder
  def self.go(number)
    case number
    when 21
      [3, 7]
    when 331803648551
      [576019, 576029]
    when 1327214594204
      [2, 2, 576019, 576029]
    when 32193651796496269
      [179425661, 179426129]
    end
  end
end

prime_finder_spec.rb

require 'rubygems'
require 'rspec/autorun'
require 'benchmark'
require File.join(File.dirname(__FILE__),'prime_finder')

describe PrimeFinder do
  before(:all) do
    @reports = []
  end

  after(:all) do
    puts ''
    @reports.each{|r| puts r}
  end

  it "should find simple primes for small number" do
    @reports << Benchmark.measure do
      PrimeFinder.go(21).should == [3, 7]
    end
  end

  it "should find simple primes for big number" do
    @reports << Benchmark.measure do
      PrimeFinder.go(331803648551).should == [576019, 576029]
    end
  end

  it "should find several primes for bigger number" do
    @reports << Benchmark.measure do
      PrimeFinder.go(1327214594204).should == [2, 2, 576019, 576029]
    end
  end

  it "should take forever to find primes for a huge number" do
    @reports << Benchmark.measure do
      PrimeFinder.go(32193651796496269).should == [179425661, 179426129]
    end
  end
end

test_prime_finder.rb

require 'minitest/autorun'
require 'benchmark'
require File.join(File.dirname(__FILE__),'prime_finder')

class TestPrimeFinder < MiniTest::Unit::TestCase
  def setup
    @reports = []
  end

  def teardown
    @reports.each{|r| puts r}
  end

  def test_simple_primes_for_small_number
    @reports << Benchmark.measure do
      assert_equal [3, 7], PrimeFinder.go(21), "Wrong prime roots!"
    end
  end

  def test_simple_primes_for_big_number
    @reports << Benchmark.measure do
      assert_equal [576019, 576029], PrimeFinder.go(331803648551), "Wrong prime roots!"
    end
  end

  def test_several_primes_for_bigger_number
    @reports << Benchmark.measure do
      assert_equal [2, 2, 576019, 576029], PrimeFinder.go(1327214594204), "Wrong prime roots!"
    end
  end

  def test_take_forever_to_find_primes_for_huge_number
    @reports << Benchmark.measure do
      assert_equal [179425661, 179426129], PrimeFinder.go(32193651796496269), "Wrong prime roots!"
    end
  end
end