--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.ruby.test/src/com/oracle/truffle/ruby/test/language/RedefinitionTests.java	Mon Jan 06 17:12:09 2014 +0000
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2013 Oracle and/or its affiliates. All rights reserved. This
+ * code is released under a tri EPL/GPL/LGPL license. You can use it,
+ * redistribute it and/or modify it under the terms of the:
+ *
+ * Eclipse Public License version 1.0
+ * GNU General Public License version 2
+ * GNU Lesser General Public License version 2.1
+ */
+package com.oracle.truffle.ruby.test.language;
+
+import org.junit.*;
+
+import com.oracle.truffle.ruby.test.*;
+
+/**
+ * Test that methods can be redefined.
+ */
+public class RedefinitionTests extends RubyTests {
+
+    /**
+     * Test that a method on Fixnum can be redefined and that we will use the new definition. The
+     * call that expects to find the redefinition needs to have already been specialized, which is
+     * why do it through a method.
+     */
+    @Test
+    public void testSimpleOperatorRedefinition() {
+        assertPrints("3\n-1\n", //
+                        "def add(x, y)\n" + //
+                                        "    x + y\n" + //
+                                        "end\n" + //
+                                        "puts add(1, 2)\n" + //
+                                        "class Fixnum\n" + //
+                                        "    def +(other)\n" + //
+                                        "        self - other\n" + //
+                                        "    end\n" + //
+                                        "end\n" + //
+                                        "puts add(1, 2)\n");
+    }
+
+    /**
+     * This is quite a subtle test. We redefine Float#+. We have a method which calls +. It is
+     * initially specialized to Fixnum, but then used with Float. The tricky bit is that Float has
+     * not been redefined since the operator has been specialized. The operator thinks it is up to
+     * date. When we emit a + node, we need to check if any class that that node could specialize to
+     * has been redefined.
+     */
+    @Test
+    public void testSpecialisationConsidersRedefinitionInOtherClasses() {
+        assertPrints("16\n12.25\n", //
+                        "def add(a, b)\n" + //
+                                        "    a + b\n" + //
+                                        "end\n" + //
+                                        "class Float\n" + //
+                                        "    def +(other)\n" + //
+                                        "        self - other\n" + //
+                                        "    end\n" + //
+                                        "end\n" + //
+                                        "puts add(14, 2)\n" + //
+                                        "puts add(14.5, 2.25)");
+    }
+
+}