Add a row in the network tray to inform users to turn Bluetooth on to enable Tether.

ash/system/tray/tray_info_label_unittest.cc

+// 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.
+
+#include "ash/system/tray/tray_info_label.h"
+
+#include "ash/test/ash_test_base.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/accessibility/ax_node_data.h"
+
+namespace ash {
+
+namespace {
+
+class TestClickEvent : public ui::Event {
+ public:
+  TestClickEvent() : ui::Event(ui::ET_MOUSE_PRESSED, base::TimeTicks(), 0) {}
+};
+
+class TestDelegate : public TrayInfoLabel::Delegate {
+ public:
+  TestDelegate() {}
+
+  const std::vector<int>& clicked_message_ids() { return clicked_message_ids_; }
+
+  void AddClickableMessageId(int message_id) {
+    clickable_message_ids_.insert(message_id);
+  }
+
+  // TrayInfoLabel::Delegate:
+  void OnLabelClicked(int message_id) override {
+    clicked_message_ids_.push_back(message_id);
+  }
+
+  bool IsLabelClickable(int message_id) const override {
+    return clickable_message_ids_.find(message_id) !=
+           clickable_message_ids_.end();
+  }
+
+ private:
+  std::unordered_set<int> clickable_message_ids_;
+  std::vector<int> clicked_message_ids_;
+};
+
+}  // namespace
+
+class TrayInfoLabelTest : public AshTestBase {
+ public:
+  void TearDown() override {
+    AshTestBase::TearDown();
+    label_.reset();
+    delegate_.reset();
+  }
+
+  void CreateLabel(bool use_delegate, int message_id) {
+    if (use_delegate)
+      delegate_ = base::MakeUnique<TestDelegate>();
+
+    label_ = base::MakeUnique<TrayInfoLabel>(delegate_.get(), message_id);
+  }
+
+  void ClickOnLabel(bool expect_click_was_handled) {
+    bool click_was_handled = label_->PerformAction(TestClickEvent());
+    EXPECT_EQ(expect_click_was_handled, click_was_handled);
+  }
+
+  void VerifyClickability(bool expected_clickable) {
+    EXPECT_EQ(expected_clickable, label_->IsClickable());
+
+    ui::AXNodeData node_data;
+    label_->GetAccessibleNodeData(&node_data);
+
+    if (expected_clickable)
+      EXPECT_EQ(ui::AX_ROLE_BUTTON, node_data.role);
+    else
+      EXPECT_EQ(ui::AX_ROLE_LABEL_TEXT, node_data.role);
+  }
+
+  void VerifyClicks(const std::vector<int>& expected_clicked_message_ids) {
+    if (!delegate_) {
+      EXPECT_TRUE(expected_clicked_message_ids.empty());
+      return;
+    }
+
+    EXPECT_EQ(expected_clicked_message_ids, delegate_->clicked_message_ids());
+  }
+
+  void VerifyNoClicks() { VerifyClicks(std::vector<int>()); }
+
+ protected:
+  std::unique_ptr<TrayInfoLabel> label_;
+  std::unique_ptr<TestDelegate> delegate_;
+};
+
+TEST_F(TrayInfoLabelTest, NoDelegate) {
+  CreateLabel(false /* use_delegate */, 0 /* message_id */);
+  VerifyClickability(false);
+
+  label_->Update(1 /* message_id */);
+  VerifyClickability(false);
+
+  label_->Update(2 /* message_id */);
+  VerifyClickability(false);
+}
+
+TEST_F(TrayInfoLabelTest, PerformAction) {
+  const int kClickableMessageId1 = 1;
+  const int kClickableMessageId2 = 2;
+  const int kNonClickableMessageId = 0;
+
+  CreateLabel(true /* use_delegate */, kClickableMessageId1);
+  delegate_->AddClickableMessageId(kClickableMessageId1);
+  delegate_->AddClickableMessageId(kClickableMessageId2);
+  VerifyNoClicks();
+
+  VerifyClickability(true /* expected_clickable */);
+  ClickOnLabel(true /* expect_click_was_handled */);

[James Cook, 2017/07/18 17:26:10]

optional: Since ClickOnLabel() is only 2 lines, consider inlining all the calls.
This might make it easier to read the test linearly instead of looking up and
down in the file. EXPECT_TRUE(label_->PerformAction(...)). In general, a little
bit of copy/paste is OK in test code if it helps make the tests easier to read
top-to-bottom.

The other utility methods seem fine, since they do a lot more stuff.

[Kyle Horimoto, 2017/07/18 17:38:08]

This approach is fine as well. I requested Leslie to add that helper function to
encapsulate the creation of the TestClickEvent each time we perform a click, so
I still think it provides some value. Up to you, Leslie :)

+  VerifyClicks(std::vector<int>{kClickableMessageId1});
+
+  ClickOnLabel(true /* expect_click_was_handled */);
+  VerifyClicks(std::vector<int>{kClickableMessageId1, kClickableMessageId1});
+
+  label_->Update(kNonClickableMessageId);
+  VerifyClickability(false /* expected_clickable */);
+  ClickOnLabel(false /* expect_click_was_handled */);
+  VerifyClicks(std::vector<int>{kClickableMessageId1, kClickableMessageId1});
+
+  label_->Update(kClickableMessageId2);
+  VerifyClickability(true /* expected_clickable */);
+  ClickOnLabel(true /* expect_click_was_handled */);
+  VerifyClicks(std::vector<int>(

[Kyle Horimoto, 2017/07/18 17:10:05]

nit: Remove parentheses around the {}s.

+      {kClickableMessageId1, kClickableMessageId1, kClickableMessageId2}));
+}
+
+}  // namespace ash

[James Cook, 2017/07/18 17:26:10]

Thanks for adding a nice test suite.