Implementation for switching between recently used tabs using ctrl tilde or quoteleft.

chrome/browser/ui/tabs/tab_mru_list_manager_unittest.cc

+// Copyright (c) 2012 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.
+
+#include "chrome/browser/ui/tabs/tab_mru_list_manager.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+typedef testing::Test TabMRUListManagerTest;
+
+// Swich to MRU tab when list is empty.
+TEST_F(TabMRUListManagerTest, ListEmpty) {
+  TabMRUListManager mru_list(NULL);
+  TabContentsWrapper* contents = mru_list.GetNextMRUTab();
+  EXPECT_EQ(NULL, contents);
+}
+
+// Insert 3 tabs and switch between first and 3rd tab
+TEST_F(TabMRUListManagerTest, ToggleMRUTabs) {
+  TabMRUListManager mru_list(NULL);
+  TabContentsWrapper* contents1 = (TabContentsWrapper*) 0xfffffff1;
+  TabContentsWrapper* contents2 = (TabContentsWrapper*) 0xfffffff2;
+  TabContentsWrapper* contents3 = (TabContentsWrapper*) 0xfffffff3;
+
+  mru_list.TabInsertedAt(contents1, 0, true);
+  mru_list.TabInsertedAt(contents2, 1, true);
+  mru_list.TabInsertedAt(contents3, 2, true);
+
+  // content3 will be the current active tab and contents2 will be
+  // the most recently used tab.
+  // Now activate contents1 so that we toggle between contents1 and
+  // contents3
+  mru_list.ActiveTabChanged(contents3, contents1, 0, true);
+
+  // Now calling GetNextMRUTab will return contents3 because we
+  // shifted to contents1 from contents3,
+  TabContentsWrapper* contents = mru_list.GetNextMRUTab();
+  EXPECT_EQ(contents, contents3);
+}
+
+// Detach a MRU tab and check the behaviour
+// Insert 3 tabs and switch between first and 3rd tab
+TEST_F(TabMRUListManagerTest, DetachMRUTabs) {
+  TabMRUListManager mru_list(NULL);
+  TabContentsWrapper* contents1 = (TabContentsWrapper*) 0xfffffff1;
+  TabContentsWrapper* contents2 = (TabContentsWrapper*) 0xfffffff2;
+  TabContentsWrapper* contents3 = (TabContentsWrapper*) 0xfffffff3;
+
+  mru_list.TabInsertedAt(contents1, 0, true);
+  mru_list.TabInsertedAt(contents2, 1, true);
+  mru_list.TabInsertedAt(contents3, 2, true);
+
+  // content3 will be the current active tab and contents2 will be
+  // the most recently used tab.
+  // Now activate contents1 so that we toggle between contents1 and
+  // contents3
+  mru_list.ActiveTabChanged(contents3, contents1, 0, true);
+
+  // Now calling GetNextMRUTab will return contents3 because we
+  // shifted to contents1 from contents3,
+  TabContentsWrapper* contents = mru_list.GetNextMRUTab();
+  EXPECT_EQ(contents, contents3);
+
+  // Detach contents3 and then the next MRU tab should be contents2
+  // as per MRU order.
+  mru_list.TabDetachedAt(contents3, 2);
+  contents = mru_list.GetNextMRUTab();
+  EXPECT_EQ(contents, contents2);
+}