[Tab Scrolling] Add unit tests for TabStripRegionView.

Boiler plate setup to enable tests for TabStripRegionView with and
without scrolling.

Added one test for scrolling to ensure the TabStrip can grow larger than
its parent.

Bug: 1141674
Change-Id: I7ae9ba8a1f6b8f2f8f899002dcea51cc1c64edd4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2493483
Commit-Queue: Charlene Yan <cyan@chromium.org>
Reviewed-by: Peter Boström <pbos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822854}

chrome/browser/ui/views/frame/tab_strip_region_view_unittest.cc

+// Copyright (c) 2020 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/views/frame/tab_strip_region_view.h"
+
+#include <memory>
+#include <string>
+
+#include "base/feature_list.h"
+#include "base/test/scoped_feature_list.h"
+#include "chrome/browser/ui/layout_constants.h"
+#include "chrome/browser/ui/ui_features.h"
+#include "chrome/browser/ui/views/tabs/fake_base_tab_strip_controller.h"
+#include "chrome/browser/ui/views/tabs/tab.h"
+#include "chrome/browser/ui/views/tabs/tab_strip.h"
+#include "chrome/browser/ui/views/tabs/tab_style_views.h"
+#include "chrome/test/views/chrome_views_test_base.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gfx/animation/animation_test_api.h"
+#include "ui/views/layout/flex_layout.h"
+#include "ui/views/view.h"
+#include "ui/views/widget/widget.h"
+
+// TabStripRegionViewTestBase contains no test cases.
+class TabStripRegionViewTestBase : public ChromeViewsTestBase {
+ public:
+  explicit TabStripRegionViewTestBase(bool has_scrolling)
+      : animation_mode_reset_(gfx::AnimationTestApi::SetRichAnimationRenderMode(
+            gfx::Animation::RichAnimationRenderMode::FORCE_ENABLED)) {
+    if (has_scrolling) {
+      scoped_feature_list_.InitWithFeatures({features::kScrollableTabStrip},
+                                            {});
+    } else {
+      scoped_feature_list_.InitWithFeatures({},
+                                            {features::kScrollableTabStrip});
+    }
+  }
+  TabStripRegionViewTestBase(const TabStripRegionViewTestBase&) = delete;
+  TabStripRegionViewTestBase& operator=(const TabStripRegionViewTestBase&) =
+      delete;
+  ~TabStripRegionViewTestBase() override = default;
+
+  void SetUp() override {
+    ChromeViewsTestBase::SetUp();
+
+    auto controller = std::make_unique<FakeBaseTabStripController>();
+    controller_ = controller.get();
+    auto tab_strip = std::make_unique<TabStrip>(
+        std::unique_ptr<TabStripController>(controller.release()));
+    tab_strip_ = tab_strip.get();
+    controller_->set_tab_strip(tab_strip_);
+    widget_ = CreateTestWidget();
+    tab_strip_region_view_ = widget_->SetContentsView(
+        std::make_unique<TabStripRegionView>(std::move(tab_strip)));
+
+    // Prevent hover cards from appearing when the mouse is over the tab. Tests
+    // don't typically account for this possibly, so it can cause unrelated
+    // tests to fail due to tab data not being set. See crbug.com/1050012.
+    Tab::SetShowHoverCardOnMouseHoverForTesting(false);
+  }
+
+  void TearDown() override {
+    widget_.reset();
+    ChromeViewsTestBase::TearDown();
+  }
+
+ protected:
+  int GetInactiveTabWidth() { return tab_strip_->GetInactiveTabWidth(); }
+  void CompleteAnimationAndLayout() {
+    tab_strip_->CompleteAnimationAndLayout();
+  }
+
+  // Owned by TabStrip.
+  FakeBaseTabStripController* controller_ = nullptr;
+  TabStrip* tab_strip_ = nullptr;
+  TabStripRegionView* tab_strip_region_view_ = nullptr;
+  std::unique_ptr<views::Widget> widget_;
+
+ private:
+  std::unique_ptr<base::AutoReset<gfx::Animation::RichAnimationRenderMode>>
+      animation_mode_reset_;
+  base::test::ScopedFeatureList scoped_feature_list_;
+};
+
+// TabStripRegionViewTest contains tests that will run with scrolling enabled
+// and disabled.
+class TabStripRegionViewTest : public TabStripRegionViewTestBase,
+                               public testing::WithParamInterface<bool> {
+ public:
+  TabStripRegionViewTest() : TabStripRegionViewTestBase(GetParam()) {}
+  TabStripRegionViewTest(const TabStripRegionViewTest&) = delete;
+  TabStripRegionViewTest& operator=(const TabStripRegionViewTest&) = delete;
+  ~TabStripRegionViewTest() override = default;
+};
+
+class TabStripRegionViewTestWithScrollingDisabled
+    : public TabStripRegionViewTestBase {
+ public:
+  TabStripRegionViewTestWithScrollingDisabled()
+      : TabStripRegionViewTestBase(false) {}
+  TabStripRegionViewTestWithScrollingDisabled(
+      const TabStripRegionViewTestWithScrollingDisabled&) = delete;
+  TabStripRegionViewTestWithScrollingDisabled& operator=(
+      const TabStripRegionViewTestWithScrollingDisabled&) = delete;
+  ~TabStripRegionViewTestWithScrollingDisabled() override = default;
+
+ private:
+};
+
+// When scrolling is disabled, the tab strip cannot be larger than the container
+// so tabs that do not fit in the tabstrip will become invisible. This is the
+// opposite behavior from
+// TabStripRegionViewTestWithScrollingEnabled.TabStripCanBeLargerThanContainer.
+TEST_F(TabStripRegionViewTestWithScrollingDisabled,
+       TabStripCannotBeLargerThanContainer) {
+  const int minimum_active_width = TabStyleViews::GetMinimumInactiveWidth();
+  controller_->AddTab(0, true);
+  CompleteAnimationAndLayout();
+
+  // Add tabs to the tabstrip until it is full.
+  while (GetInactiveTabWidth() > minimum_active_width) {
+    controller_->AddTab(0, false);
+    CompleteAnimationAndLayout();
+  }
+
+  // Add a few more tabs after the tabstrip is full to ensure tabs added
+  // afterwards are not visible.
+  for (int i = 0; i < 5; i++) {
+    controller_->AddTab(0, false);
+    CompleteAnimationAndLayout();
+  }
+  EXPECT_LT(tab_strip_->width(), tab_strip_region_view_->width());
+  EXPECT_FALSE(
+      tab_strip_->tab_at(tab_strip_->GetModelCount() - 1)->GetVisible());
+}
+
+class TabStripRegionViewTestWithScrollingEnabled
+    : public TabStripRegionViewTestBase {
+ public:
+  TabStripRegionViewTestWithScrollingEnabled()
+      : TabStripRegionViewTestBase(true) {}
+  TabStripRegionViewTestWithScrollingEnabled(
+      const TabStripRegionViewTestWithScrollingEnabled&) = delete;
+  TabStripRegionViewTestWithScrollingEnabled& operator=(
+      const TabStripRegionViewTestWithScrollingEnabled&) = delete;
+  ~TabStripRegionViewTestWithScrollingEnabled() override = default;
+};
+
+// When scrolling is enabled, the tab strip can grow to be larger than the
+// container. This is the opposite behavior from
+// TabStripRegionViewTestWithScrollingDisabled.
+// TabStripCannotBeLargerThanContainer.
+TEST_F(TabStripRegionViewTestWithScrollingEnabled,
+       TabStripCanBeLargerThanContainer) {
+  const int minimum_active_width = TabStyleViews::GetMinimumInactiveWidth();
+  controller_->AddTab(0, true);
+  CompleteAnimationAndLayout();
+
+  // Add tabs to the tabstrip until it is full and should start overflowing.
+  while (GetInactiveTabWidth() > minimum_active_width) {
+    controller_->AddTab(0, false);
+    CompleteAnimationAndLayout();
+  }
+
+  // Add a few more tabs after the tabstrip is full to ensure the tabstrip
+  // starts scrolling.
+  for (int i = 0; i < 5; i++) {
+    controller_->AddTab(0, false);
+    CompleteAnimationAndLayout();
+  }
+  EXPECT_GT(tab_strip_->width(), tab_strip_region_view_->width());
+  EXPECT_TRUE(
+      tab_strip_->tab_at(tab_strip_->GetModelCount() - 1)->GetVisible());
+}
+
+INSTANTIATE_TEST_SUITE_P(All,
+                         TabStripRegionViewTest,
+                         ::testing::Values(true, false));

chrome/browser/ui/views/tabs/tab_strip.h

@@ -367,6 +367,7 @@ class TabStrip : public views::View,
   friend class TabHoverCardBubbleViewBrowserTest;
   friend class TabHoverCardBubbleViewInteractiveUiTest;
   friend class TabStripTest;
+  friend class TabStripRegionViewTestBase;
 
   class TabContextMenuController : public views::ContextMenuController {
    public:

chrome/test/BUILD.gn

@@ -5968,6 +5968,7 @@ test("unit_tests") {
       "../browser/ui/views/frame/browser_non_client_frame_view_unittest.cc",
       "../browser/ui/views/frame/browser_view_layout_unittest.cc",
       "../browser/ui/views/frame/browser_view_unittest.cc",
+      "../browser/ui/views/frame/tab_strip_region_view_unittest.cc",
       "../browser/ui/views/frame/test_with_browser_view.cc",
       "../browser/ui/views/frame/test_with_browser_view.h",
       "../browser/ui/views/frame/web_contents_close_handler_unittest.cc",