Test coverage for bug in WmWindowAura::OnWindowVisibilityChanged()

ash/common/wm_window_unittest.cc

Index: ash/common/wm_window_unittest.cc
diff --git a/ash/common/wm_window_unittest.cc b/ash/common/wm_window_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ed2dc3d7b5194b8810993cb856f7f5a2a9f17c47
--- /dev/null
+++ b/ash/common/wm_window_unittest.cc
@@ -0,0 +1,82 @@
+// Copyright 2016 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 "ash/common/wm_window.h"
+
+#include <memory>
+
+#include "ash/common/test/ash_test.h"
+#include "ash/common/wm_window_observer.h"
+
+namespace ash {
+
+using WmWindowTest = AshTest;
+
+namespace {
+
+// Tracks calls to OnWindowVisibilityChanged().
+class VisibilityObserver : public WmWindowObserver {
+ public:
+  // Attaches a WmWindowObserver to |window_to_add_observer_to| and sets
+  // |last_observed_window_| and |last_observed_visible_value_| to the values
+  // of the last call to OnWindowVisibilityChanged().
+  explicit VisibilityObserver(WmWindow* window_to_add_observer_to)
+      : window_to_add_observer_to_(window_to_add_observer_to) {
+    window_to_add_observer_to_->AddObserver(this);
+  }
+  ~VisibilityObserver() override {
+    window_to_add_observer_to_->RemoveObserver(this);
+  }
+
+  // The values last supplied to OnWindowVisibilityChanged().
+  WmWindow* last_observed_window() { return last_observed_window_; }
+  bool last_observed_visible_value() const {
+    return last_observed_visible_value_;
+  }
+
+  // WmWindowObserver:
+  void OnWindowVisibilityChanged(WmWindow* window, bool visible) override {
+    last_observed_window_ = window;
+    last_observed_visible_value_ = visible;
+  }
+
+ private:
+  WmWindow* window_to_add_observer_to_;
+  WmWindow* last_observed_window_ = nullptr;
+  bool last_observed_visible_value_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(VisibilityObserver);
+};
+
+}  // namespace
+
+// Verifies OnWindowVisibilityChanged() is called on a WmWindowObserver attached
+// to the parent when the child window's visibility changes.
+TEST_F(WmWindowTest, OnWindowVisibilityChangedCalledOnAncestor) {
+  std::unique_ptr<WindowOwner> window_owner = CreateTestWindow();
+  WmWindow* window = window_owner->window();
+  std::unique_ptr<WindowOwner> child_owner =
+      CreateChildWindow(window_owner->window());
+  WmWindow* child_window = child_owner->window();
+  VisibilityObserver observer(window);
+  child_window->Hide();
+  EXPECT_EQ(child_window, observer.last_observed_window());
+  EXPECT_EQ(false, observer.last_observed_visible_value());

[James Cook, 2016/09/28 19:02:49]

nit: I think we usually EXPECT_FALSE

(and below)

[sky, 2016/09/28 19:30:16]

Done.

+}
+
+// Verifies OnWindowVisibilityChanged() is called on a WmWindowObserver attached
+// to a child when the parent window's visibility changes.
+TEST_F(WmWindowTest, OnWindowVisibilityChangedCalledOnChild) {
+  std::unique_ptr<WindowOwner> window_owner = CreateTestWindow();
+  WmWindow* window = window_owner->window();

[James Cook, 2016/09/28 19:02:49]

optional: parent_window ?

[sky, 2016/09/28 19:30:16]

Done.

+  std::unique_ptr<WindowOwner> child_owner =
+      CreateChildWindow(window_owner->window());
+  WmWindow* child_window = child_owner->window();
+  VisibilityObserver observer(child_window);
+  window->Hide();
+  EXPECT_EQ(window, observer.last_observed_window());
+  EXPECT_EQ(false, observer.last_observed_visible_value());
+}
+
+}  // namespace ash