diff --git a/ChangeLog b/ChangeLog
index 02acc2ebba..66773ac554 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Jul 30 21:56:18 2009  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* test/ruby/test_rand.rb: add tests for Random class.
+
 Thu Jul 30 21:48:56 2009  Yusuke Endoh  <mame@tsg.ne.jp>
 
 	* random.c (init_genrand): ensure invariant of mt->next and mt->left.
diff --git a/test/ruby/test_rand.rb b/test/ruby/test_rand.rb
index f32696cf10..2f2e772c1b 100644
--- a/test/ruby/test_rand.rb
+++ b/test/ruby/test_rand.rb
@@ -168,4 +168,194 @@ class TestRand < Test::Unit::TestCase
   def test_big_seed
     assert_random_int(%w(1143843490), 0x100000000, 2**1000000-1)
   end
+
+  def test_random_gc
+    r = Random.new(0)
+    %w(2357136044 2546248239 3071714933).each do |w|
+      assert_equal(w.to_i, r.int(0x100000000))
+    end
+    GC.start
+    %w(3626093760 2588848963 3684848379).each do |w|
+      assert_equal(w.to_i, r.int(0x100000000))
+    end
+  end
+
+  def test_random_type_error
+    assert_raise(TypeError) { Random.new(Object.new) }
+    assert_raise(TypeError) { Random.new(0).int(Object.new) }
+  end
+
+  def test_random_argument_error
+    assert_raise(ArgumentError) { Random.new(0).float(0, 0) }
+  end
+
+  def test_random_seed
+    assert_equal(0, Random.new(0).seed)
+    assert_equal(0x100000000, Random.new(0x100000000).seed)
+    assert_equal(2**100, Random.new(2**100).seed)
+  end
+
+  def test_random_dup
+    r1 = Random.new(0)
+    r2 = r1.dup
+    %w(2357136044 2546248239 3071714933).each do |w|
+      assert_equal(w.to_i, r1.int(0x100000000))
+    end
+    %w(2357136044 2546248239 3071714933).each do |w|
+      assert_equal(w.to_i, r2.int(0x100000000))
+    end
+    r2 = r1.dup
+    %w(3626093760 2588848963 3684848379).each do |w|
+      assert_equal(w.to_i, r1.int(0x100000000))
+    end
+    %w(3626093760 2588848963 3684848379).each do |w|
+      assert_equal(w.to_i, r2.int(0x100000000))
+    end
+  end
+
+  def test_random_state
+    state = <<END
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+2254080
+END
+    state = state.split.join.to_i
+    r = Random.new(0)
+    srand(0)
+    assert_equal(state, r.instance_eval { state })
+    assert_equal(state, Random.instance_eval { state })
+    r.int(0x100)
+    assert_equal(state, r.instance_eval { state })
+  end
+
+  def test_random_left
+    r = Random.new(0)
+    assert_equal(1, r.instance_eval { left })
+    r.int(0x100)
+    assert_equal(624, r.instance_eval { left })
+    r.int(0x100)
+    assert_equal(623, r.instance_eval { left })
+    srand(0)
+    assert_equal(1, Random.instance_eval { left })
+    rand(0x100)
+    assert_equal(624, Random.instance_eval { left })
+    rand(0x100)
+    assert_equal(623, Random.instance_eval { left })
+  end
+
+  def test_random_bytes
+    r = Random.new(0)
+    assert_equal("", r.bytes(0))
+    assert_equal("\xAC".force_encoding("ASCII-8BIT"), r.bytes(1))
+    assert_equal("/\xAA\xC4\x97u\xA6\x16\xB7\xC0\xCC".force_encoding("ASCII-8BIT"),                                                                                                                              r.bytes(10))
+  end
+
+  def test_random_range
+    r = Random.new(0)
+    %w(9 5 8).each {|w| assert_equal(w.to_i, r.int(5..9)) }
+    %w(-237 731 383).each {|w| assert_equal(w.to_i, r.int(-1000..1000)) }
+    %w(1267650600228229401496703205382
+       1267650600228229401496703205384
+       1267650600228229401496703205383).each do |w|
+      assert_equal(w.to_i, r.int(2**100+5..2**100+9))
+    end
+  end
+
+  def test_random_float
+    r = Random.new(0)
+    assert_in_delta(0.5488135039273248, r.float, 0.0001)
+    assert_in_delta(0.7151893663724195, r.float, 0.0001)
+    assert_in_delta(0.6027633760716439, r.float, 0.0001)
+    assert_in_delta(1.0897663659937937, r.float(2), 0.0001)
+    assert_in_delta(5.3704626067153264e+29, r.float(2**100), 10**25)
+
+    # is this intentional?
+    assert_raise(TypeError) { r.float(1..2) }
+  end
+
+  def test_random_equal
+    r = Random.new(0)
+    assert(r == r)
+    assert(r == r.dup)
+    r1 = r.dup
+    r2 = r.dup
+    r1.int(0x100)
+    assert(r1 != r2)
+    r2.int(0x100)
+    assert(r1 == r2)
+  end
 end