Multicast DNS implementation (initial)

net/test/fake_time_system.h

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NET_TEST_FAKE_TIME_SYSTEM_H_
+#define NET_TEST_FAKE_TIME_SYSTEM_H_
+
+#include <queue>
+
+#include "base/callback.h"
+#include "base/task_runner.h"
+#include "base/time/clock.h"
+
+namespace net {
+
+// This class implements both base::Clock and base::TaskRunner, and can
+// be used to simulate actual time in unit test for classes that both query
+// for the current time and shedule future tasks using a TaskRunner.
+
+class FakeTimeSystem : public base::Clock, public base::TaskRunner {
+ public:
+  class Task {
+   public:
+    Task(base::Time time, base::Closure task);
+    ~Task();
+
+    bool operator<(const Task &other) const;
+
+    const base::Closure& closure() const { return task_; }
+    const base::Time time() const { return time_; }
+
+   private:
+    base::Closure task_;
+    base::Time time_;
+  };
+
+  FakeTimeSystem();
+
+  void SetNow(base::Time now);
+
+  // Runs pending tasks until the queue is empty. Runs only tasks
+  // that are supposed to be run after |now_|.
+  void RunPendingTasks();
+
+  virtual base::Time Now() OVERRIDE;
+
+  virtual bool PostDelayedTask(const tracked_objects::Location& from_here,
+                               const base::Closure& task,
+                               base::TimeDelta delay) OVERRIDE;
+
+  virtual bool RunsTasksOnCurrentThread() const OVERRIDE;
+
+ private:
+  virtual ~FakeTimeSystem();
+
+  base::Time now_;
+  std::priority_queue<Task> tasks_;
+
+  DISALLOW_COPY_AND_ASSIGN(FakeTimeSystem);
+};
+}
+
+#endif  // NET_TEST_FAKE_TIME_SYSTEM_H_