diff --git a/test/ruby/test_fixnum.rb b/test/ruby/test_fixnum.rb
index 4cf73fb4c8..f9f9052f76 100644
--- a/test/ruby/test_fixnum.rb
+++ b/test/ruby/test_fixnum.rb
@@ -29,8 +29,40 @@ class TestFixnum < Test::Unit::TestCase
     assert_equal(0x4000000000000000, 0x3fffffffffffffff.succ, "[ruby-dev:31190]")
   end
 
-  def test_plus
-    assert_equal(0x4000000000000000, 0x3fffffffffffffff+1)
+  def test_pred
+    assert_equal(-0x40000001, (-0x40000000).pred)
+    assert_equal(-0x4000000000000001, (-0x4000000000000000).pred)
   end
 
+  def test_plus
+    assert_equal(0x40000000, 0x3fffffff+1)
+    assert_equal(0x4000000000000000, 0x3fffffffffffffff+1)
+    assert_equal(-0x40000001, (-0x40000000)+(-1))
+    assert_equal(-0x4000000000000001, (-0x4000000000000000)+(-1))
+    assert_equal(-0x80000000, (-0x40000000)+(-0x40000000))
+  end
+
+  def test_sub
+    assert_equal(0x40000000, 0x3fffffff-(-1))
+    assert_equal(0x4000000000000000, 0x3fffffffffffffff-(-1))
+    assert_equal(-0x40000001, (-0x40000000)-1)
+    assert_equal(-0x4000000000000001, (-0x4000000000000000)-1)
+    assert_equal(-0x80000000, (-0x40000000)-0x40000000)
+  end
+
+  def test_mult
+    assert_equal(0x40000000, 0x20000000*2)
+    assert_equal(0x4000000000000000, 0x2000000000000000*2)
+    assert_equal(-0x40000001, 33025*(-32513))
+    assert_equal(-0x4000000000000001, 1380655685*(-3340214413))
+    assert_equal(0x40000000, (-0x40000000)*(-1))
+  end
+
+  def test_div
+    assert_equal(0x40000000, 0xc0000000/3)
+    assert_equal(0x4000000000000000, 0xc000000000000000/3)
+    assert_equal(-0x40000001, 0xc0000003/(-3))
+    assert_equal(-0x4000000000000001, 0xc000000000000003/(-3))
+    assert_equal(0x40000000, (-0x40000000)/(-1), "[ruby-dev:31210]")
+  end
 end