ruby--ruby/test/ruby/test_rand.rb

require 'test/unit'

class TestRand < Test::Unit::TestCase
  def assert_random_int(ws, m, init = 0)
    srand(init)
    rnds = [Random.new(init)]
    ws.each do |w|
      w = w.to_i
      assert_equal(w, rand(m))
      rnds.each do |rnd|
        assert_equal(w, rnd.int(m))
      end
      rnds << Marshal.load(Marshal.dump(rnds[-1]))
    end
  end

  def test_mt
    assert_random_int(%w(1067595299  955945823  477289528 4107218783 4228976476),
                      0x100000000, 0x00000456_00000345_00000234_00000123)
  end

  def test_0x3fffffff
    assert_random_int(%w(209652396 398764591 924231285 404868288 441365315),
                      0x3fffffff)
  end

  def test_0x40000000
    assert_random_int(%w(209652396 398764591 924231285 404868288 441365315),
                      0x40000000)
  end

  def test_0x40000001
    assert_random_int(%w(209652396 398764591 924231285 441365315 192771779),
                      0x40000001)
  end

  def test_0xffffffff
    assert_random_int(%w(2357136044 2546248239 3071714933 3626093760 2588848963),
                      0xffffffff)
  end

  def test_0x100000000
    assert_random_int(%w(2357136044 2546248239 3071714933 3626093760 2588848963),
                      0x100000000)
  end

  def test_0x100000001
    assert_random_int(%w(2546248239 1277901399 243580376 1171049868 2051556033),
                      0x100000001)
  end

  def test_rand_0x100000000
    assert_random_int(%w(4119812344 3870378946 80324654 4294967296 410016213),
                      0x100000001, 311702798)
  end

  def test_0x1000000000000
    assert_random_int(%w(11736396900911
                         183025067478208
                         197104029029115
                         130583529618791
                         180361239846611),
                      0x1000000000000)
  end

  def test_0x1000000000001
    assert_random_int(%w(187121911899765
                         197104029029115
                         180361239846611
                         236336749852452
                         208739549485656),
                      0x1000000000001)
  end

  def test_0x3fffffffffffffff
    assert_random_int(%w(900450186894289455
                         3969543146641149120
                         1895649597198586619
                         827948490035658087
                         3203365596207111891),
                      0x3fffffffffffffff)
  end

  def test_0x4000000000000000
    assert_random_int(%w(900450186894289455
                         3969543146641149120
                         1895649597198586619
                         827948490035658087
                         3203365596207111891),
                      0x4000000000000000)
  end

  def test_0x4000000000000001
    assert_random_int(%w(900450186894289455
                         3969543146641149120
                         1895649597198586619
                         827948490035658087
                         2279347887019741461),
                      0x4000000000000001)
  end

  def test_neg_0x10000000000
    ws = %w(455570294424 1073054410371 790795084744 2445173525 1088503892627)
    assert_random_int(ws, 0x10000000000, 3)
    assert_random_int(ws, -0x10000000000, 3)
  end

  def test_neg_0x10000
    ws = %w(2732 43567 42613 52416 45891)
    assert_random_int(ws, 0x10000)
    assert_random_int(ws, -0x10000)
  end

  def test_types
    srand(0)
    rnd = Random.new(0)
    assert_equal(44, rand(100.0))
    assert_equal(44, rnd.int(100.0))
    assert_equal(1245085576965981900420779258691, rand((2**100).to_f))
    assert_equal(1245085576965981900420779258691, rnd.int((2**100).to_f))
    assert_equal(914679880601515615685077935113, rand(-(2**100).to_f))
    assert_equal(914679880601515615685077935113, rnd.int(-(2**100).to_f))

    srand(0)
    rnd = Random.new(0)
    assert_equal(997707939797331598305742933184, rand(2**100))
    assert_equal(997707939797331598305742933184, rnd.int(2**100))
    assert_in_delta(0.602763376071644, rand((2**100).coerce(0).first),
                    0.000000000000001)
    assert_equal(0, rnd.int((2**100).coerce(0).first))

    srand(0)
    rnd = Random.new(0)
    assert_in_delta(0.548813503927325, rand(nil),
                    0.000000000000001)
    assert_in_delta(0.548813503927325, rnd.float(),
                    0.000000000000001)
    srand(0)
    rnd = Random.new(0)
    o = Object.new
    def o.to_int; 100; end
    assert_equal(44, rand(o))
    assert_equal(44, rnd.int(o))
    assert_equal(47, rand(o))
    assert_equal(47, rnd.int(o))
    assert_equal(64, rand(o))
    assert_equal(64, rnd.int(o))
  end

  def test_srand
    srand
    assert_kind_of(Integer, rand(2))
    assert_kind_of(Integer, Random.new.int(2))

    srand(2**100)
    rnd = Random.new(2**100)
    %w(3258412053).each {|w|
      assert_equal(w.to_i, rand(0x100000000))
      assert_equal(w.to_i, rnd.int(0x100000000))
    }
  end

  def test_shuffle
    srand(0)
    assert_equal([1,4,2,5,3], [1,2,3,4,5].shuffle)
  end

  def test_big_seed
    srand(2**1000000-1)
    assert_equal(1143843490, rand(0x100000000))
  end
end