Introduce WebStateList to manage a list of web::WebState.

ios/shared/chrome/browser/tabs/web_state_list_unittest.mm

+// Copyright 2017 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.
+
+#import "ios/shared/chrome/browser/tabs/web_state_list.h"
+
+#include "base/macros.h"
+#include "base/memory/ptr_util.h"
+#include "base/supports_user_data.h"
+#import "ios/shared/chrome/browser/tabs/web_state_list_observer.h"
+#import "ios/web/public/test/fakes/test_web_state.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/platform_test.h"
+
+namespace {
+const char kURL0[] = "https://chromium.org/0";
+const char kURL1[] = "https://chromium.org/1";
+const char kURL2[] = "https://chromium.org/2";
+const char kSupportsUserDataDeathGuardKey = '\0';
+
+// A base::SupportsUserData::Data that tracks whether a base::SupportsUserData
+// has been deleted (the fact is recorded in a provided pointer as part of the
+// object destruction).
+class SupportsUserDataDeathGuard : public base::SupportsUserData::Data {
+ public:
+  explicit SupportsUserDataDeathGuard(bool* object_was_destroyed)
+      : object_was_destroyed_(object_was_destroyed) {
+    *object_was_destroyed_ = false;
+  }
+
+  ~SupportsUserDataDeathGuard() override { *object_was_destroyed_ = true; }
+
+ private:
+  bool* object_was_destroyed_;
+
+  DISALLOW_COPY_AND_ASSIGN(SupportsUserDataDeathGuard);
+};
+
+// WebStateList observer that records which events have been called by the
+// WebStateList.
+class WebStateListTestObserver : public WebStateListObserver {
+ public:
+  WebStateListTestObserver() = default;
+
+  // Reset statistics whether events have been called.
+  void ResetStatistics() {
+    web_state_inserted_called_ = false;
+    web_state_moved_called_ = false;
+    web_state_replaced_called_ = false;
+    web_state_detached_called_ = false;
+  }
+
+  // Returns whether WebStateInsertedAt was invoked.
+  bool web_state_inserted_called() const { return web_state_inserted_called_; }
+
+  // Returns whether WebStateMoved was invoked.
+  bool web_state_moved_called() const { return web_state_moved_called_; }
+
+  // Returns whether WebStateReplacedAt was invoked.
+  bool web_state_replaced_called() const { return web_state_replaced_called_; }
+
+  // Returns whether WebStateDetachedAt was invoked.
+  bool web_state_detached_called() const { return web_state_detached_called_; }
+
+  // WebStateListObserver implementation.
+  void WebStateInsertedAt(WebStateList* web_state_list,
+                          web::WebState* web_state,
+                          int index) override {
+    web_state_inserted_called_ = true;
+  }
+
+  void WebStateMoved(WebStateList* web_state_list,
+                     web::WebState* web_state,
+                     int from_index,
+                     int to_index) override {
+    web_state_moved_called_ = true;
+  }
+
+  void WebStateReplacedAt(WebStateList* web_state_list,
+                          web::WebState* old_web_state,
+                          web::WebState* new_web_state,
+                          int index) override {
+    web_state_replaced_called_ = true;
+  }
+
+  void WebStateDetachedAt(WebStateList* web_state_list,
+                          web::WebState* web_state,
+                          int index) override {
+    web_state_detached_called_ = true;
+  }
+
+ private:
+  bool web_state_inserted_called_ = false;
+  bool web_state_moved_called_ = false;
+  bool web_state_replaced_called_ = false;
+  bool web_state_detached_called_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(WebStateListTestObserver);
+};
+}  // namespace
+
+class WebStateListTest : public PlatformTest {
+ public:
+  WebStateListTest() : web_state_list_(WebStateList::WebStateOwned) {
+    web_state_list_.AddObserver(&observer_);
+  }
+
+  ~WebStateListTest() override { web_state_list_.RemoveObserver(&observer_); }
+
+ protected:
+  WebStateList web_state_list_;
+  WebStateListTestObserver observer_;
+
+  // This method should return std::unique_ptr<> however, due to the complex
+  // ownership of Tab, WebStateList currently uses raw pointers. Change this
+  // once Tab ownership is sane, see http://crbug.com/546222 for progress.
+  web::WebState* CreateWebState(const char* url) {
+    auto test_web_state = base::MakeUnique<web::TestWebState>();
+    test_web_state->SetCurrentURL(GURL(url));
+    return test_web_state.release();
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(WebStateListTest);
+};
+
+TEST_F(WebStateListTest, IsEmpty) {
+  EXPECT_EQ(0, web_state_list_.count());
+  EXPECT_TRUE(web_state_list_.empty());
+
+  web_state_list_.InsertWebState(0, CreateWebState(kURL0));
+
+  EXPECT_TRUE(observer_.web_state_inserted_called());
+  EXPECT_EQ(1, web_state_list_.count());
+  EXPECT_FALSE(web_state_list_.empty());
+}
+
+TEST_F(WebStateListTest, InsertUrlSingle) {
+  web_state_list_.InsertWebState(0, CreateWebState(kURL0));
+
+  EXPECT_TRUE(observer_.web_state_inserted_called());
+  EXPECT_EQ(1, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+}
+
+TEST_F(WebStateListTest, InsertUrlMultiple) {
+  web_state_list_.InsertWebState(0, CreateWebState(kURL0));
+  web_state_list_.InsertWebState(0, CreateWebState(kURL1));
+  web_state_list_.InsertWebState(1, CreateWebState(kURL2));
+
+  EXPECT_TRUE(observer_.web_state_inserted_called());
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+}
+
+TEST_F(WebStateListTest, MoveWebStateAtRightByOne) {
+  web_state_list_.InsertWebState(0, CreateWebState(kURL0));
+  web_state_list_.InsertWebState(1, CreateWebState(kURL1));
+  web_state_list_.InsertWebState(2, CreateWebState(kURL2));
+
+  // Sanity check before closing WebState.
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+
+  observer_.ResetStatistics();
+  web_state_list_.MoveWebStateAt(0, 1);
+
+  EXPECT_TRUE(observer_.web_state_moved_called());
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+}
+
+TEST_F(WebStateListTest, MoveWebStateAtRightByMoreThanOne) {
+  web_state_list_.InsertWebState(0, CreateWebState(kURL0));
+  web_state_list_.InsertWebState(1, CreateWebState(kURL1));
+  web_state_list_.InsertWebState(2, CreateWebState(kURL2));
+
+  // Sanity check before closing WebState.
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+
+  observer_.ResetStatistics();
+  web_state_list_.MoveWebStateAt(0, 2);
+
+  EXPECT_TRUE(observer_.web_state_moved_called());
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+}
+
+TEST_F(WebStateListTest, MoveWebStateAtLeftByOne) {
+  web_state_list_.InsertWebState(0, CreateWebState(kURL0));
+  web_state_list_.InsertWebState(1, CreateWebState(kURL1));
+  web_state_list_.InsertWebState(2, CreateWebState(kURL2));
+
+  // Sanity check before closing WebState.
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+
+  observer_.ResetStatistics();
+  web_state_list_.MoveWebStateAt(2, 1);
+
+  EXPECT_TRUE(observer_.web_state_moved_called());
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+}
+
+TEST_F(WebStateListTest, MoveWebStateAtLeftByMoreThanOne) {
+  web_state_list_.InsertWebState(0, CreateWebState(kURL0));
+  web_state_list_.InsertWebState(1, CreateWebState(kURL1));
+  web_state_list_.InsertWebState(2, CreateWebState(kURL2));
+
+  // Sanity check before closing WebState.
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+
+  observer_.ResetStatistics();
+  web_state_list_.MoveWebStateAt(2, 0);
+
+  EXPECT_TRUE(observer_.web_state_moved_called());
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+}
+
+TEST_F(WebStateListTest, MoveWebStateAtSameIndex) {
+  web_state_list_.InsertWebState(0, CreateWebState(kURL0));
+  web_state_list_.InsertWebState(1, CreateWebState(kURL1));
+  web_state_list_.InsertWebState(2, CreateWebState(kURL2));
+
+  // Sanity check before closing WebState.
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+
+  observer_.ResetStatistics();
+  web_state_list_.MoveWebStateAt(2, 2);
+
+  EXPECT_FALSE(observer_.web_state_moved_called());
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+}
+
+TEST_F(WebStateListTest, ReplaceWebStateAt) {
+  web_state_list_.InsertWebState(0, CreateWebState(kURL0));
+  web_state_list_.InsertWebState(1, CreateWebState(kURL1));
+
+  // Sanity check before replacing WebState.
+  EXPECT_EQ(2, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+
+  observer_.ResetStatistics();
+  std::unique_ptr<web::WebState> old_web_state(
+      web_state_list_.ReplaceWebStateAt(1, CreateWebState(kURL2)));
+
+  EXPECT_TRUE(observer_.web_state_replaced_called());
+  EXPECT_EQ(2, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, old_web_state->GetVisibleURL().spec());
+}
+
+TEST_F(WebStateListTest, DetachWebStateAtIndexBegining) {
+  web_state_list_.InsertWebState(0, CreateWebState(kURL0));
+  web_state_list_.InsertWebState(1, CreateWebState(kURL1));
+  web_state_list_.InsertWebState(2, CreateWebState(kURL2));
+
+  // Sanity check before closing WebState.
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+
+  observer_.ResetStatistics();
+  web_state_list_.DetachWebStateAt(0);
+
+  EXPECT_TRUE(observer_.web_state_detached_called());
+  EXPECT_EQ(2, web_state_list_.count());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+}
+
+TEST_F(WebStateListTest, DetachWebStateAtIndexMiddle) {
+  web_state_list_.InsertWebState(0, CreateWebState(kURL0));
+  web_state_list_.InsertWebState(1, CreateWebState(kURL1));
+  web_state_list_.InsertWebState(2, CreateWebState(kURL2));
+
+  // Sanity check before closing WebState.
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+
+  observer_.ResetStatistics();
+  web_state_list_.DetachWebStateAt(1);
+
+  EXPECT_TRUE(observer_.web_state_detached_called());
+  EXPECT_EQ(2, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+}
+
+TEST_F(WebStateListTest, DetachWebStateAtIndexLast) {
+  web_state_list_.InsertWebState(0, CreateWebState(kURL0));
+  web_state_list_.InsertWebState(1, CreateWebState(kURL1));
+  web_state_list_.InsertWebState(2, CreateWebState(kURL2));
+
+  // Sanity check before closing WebState.
+  EXPECT_EQ(3, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL2, web_state_list_.GetWebStateAt(2)->GetVisibleURL().spec());
+
+  observer_.ResetStatistics();
+  web_state_list_.DetachWebStateAt(2);
+
+  EXPECT_TRUE(observer_.web_state_detached_called());
+  EXPECT_EQ(2, web_state_list_.count());
+  EXPECT_EQ(kURL0, web_state_list_.GetWebStateAt(0)->GetVisibleURL().spec());
+  EXPECT_EQ(kURL1, web_state_list_.GetWebStateAt(1)->GetVisibleURL().spec());
+}
+
+TEST_F(WebStateListTest, OwnershipBorrowed) {
+  bool web_state_was_killed = false;
+  auto test_web_state = base::MakeUnique<web::TestWebState>();
+  test_web_state->SetUserData(
+      &kSupportsUserDataDeathGuardKey,
+      base::MakeUnique<SupportsUserDataDeathGuard>(&web_state_was_killed));
+
+  auto web_state_list =
+      base::MakeUnique<WebStateList>(WebStateList::WebStateBorrowed);
+  web_state_list->InsertWebState(0, test_web_state.get());
+  EXPECT_FALSE(web_state_was_killed);
+
+  web_state_list.reset();
+  EXPECT_FALSE(web_state_was_killed);
+}
+
+TEST_F(WebStateListTest, OwnershipOwned) {
+  bool web_state_was_killed = false;
+  auto test_web_state = base::MakeUnique<web::TestWebState>();
+  test_web_state->SetUserData(
+      &kSupportsUserDataDeathGuardKey,
+      base::MakeUnique<SupportsUserDataDeathGuard>(&web_state_was_killed));
+
+  auto web_state_list =
+      base::MakeUnique<WebStateList>(WebStateList::WebStateOwned);
+  web_state_list->InsertWebState(0, test_web_state.release());
+  EXPECT_FALSE(web_state_was_killed);
+
+  web_state_list.reset();
+  EXPECT_TRUE(web_state_was_killed);
+}