[foozzie] Initial correctness fuzzer harness.

tools/foozzie/v8_mock.js

Index: tools/foozzie/v8_mock.js
diff --git a/tools/foozzie/v8_mock.js b/tools/foozzie/v8_mock.js
new file mode 100644
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+++ b/tools/foozzie/v8_mock.js
@@ -0,0 +1,77 @@
+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This is intended for permanent JS behavior changes for mocking out
+// non-deterministic behavior. For temporary suppressions, please refer to
+// v8_suppressions.js.
+// This file is loaded before each correctness test cases and won't get
+// minimized.
+
+
+// This will be overridden in the test cases. The override can be minimized.
+var __PrettyPrint = function __PrettyPrint(msg) { print(msg); };
+
+
+// All calls to f.arguments are replaced by f.mock_arguments by an external
+// script.
+Object.prototype.mock_arguments = ['x', 'y']
+
+
+// Mock Math.random.
+var __magic_index_for_mocked_random = 0
+Math.random = function(){
+  __magic_index_for_mocked_random = (__magic_index_for_mocked_random + 1) % 10
+  return __magic_index_for_mocked_random / 10.0;
+}
+
+
+// Mock Date.
+var __magic_index_for_mocked_date = 0
+var __magic_mocked_date = 1477662728696
+__magic_mocked_date_now = function(){
+  __magic_index_for_mocked_date = (__magic_index_for_mocked_date + 1) % 10
+  __magic_mocked_date = __magic_mocked_date + __magic_index_for_mocked_date + 1
+  return __magic_mocked_date
+}
+
+var __original_date = Date;
+__magic_mock_date_handler = {
+  construct: function(target, args, newTarget) {
+    if (args.length > 0) {
+      return new (Function.prototype.bind.apply(__original_date, [null].concat(args)));
+    } else {
+      return new __original_date(__magic_mocked_date_now());
+    }
+  },
+  get: function(target, property, receiver) {
+    if (property == "now") {
+      return __magic_mocked_date_now;
+    }
+  },
+}
+
+Date = new Proxy(Date, __magic_mock_date_handler);
+
+// Mock Worker.
+var __magic_index_for_mocked_worker = 0
+// TODO(machenbach): Randomize this for each test case, but keep stable during
+// comparison. Also data and random above.
+var __magic_mocked_worker_messages = [
+  undefined, 0, -1, "", "foo", 42, [], {}, [0], {"x": 0}
+]
+Worker = function(code){
+  try {
+    __PrettyPrint(eval(code));
+  } catch(e) {
+    __PrettyPrint(e);
+  }
+  this.getMessage = function(){
+    __magic_index_for_mocked_worker = (__magic_index_for_mocked_worker + 1) % 10
+    return __magic_mocked_worker_messages[__magic_index_for_mocked_worker];
+  }
+  this.postMessage = function(msg){
+    __PrettyPrint(msg);
+  }
+}
+