Add ExitFunnel to prepare for instrumenting browser exits.

components/browser_watcher/exit_funnel_win_unittest.cc

+// Copyright (c) 2014 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 "components/browser_watcher/exit_funnel_win.h"
+
+#include <map>
+
+#include "base/command_line.h"
+#include "base/process/process_handle.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/stringprintf.h"
+#include "base/test/test_reg_util_win.h"
+#include "base/threading/platform_thread.h"
+#include "base/time/time.h"
+#include "base/win/registry.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace browser_watcher {
+
+namespace {
+
+const wchar_t kRegistryPath[] = L"Software\\ExitFunnelWinTest";
+
+class ExitFunnelWinTest : public testing::Test {
+ public:
+  typedef testing::Test Super;
+  typedef std::map<base::string16, int64> EventMap;
+
+  virtual void SetUp() override {
+    Super::SetUp();
+
+    override_manager_.OverrideRegistry(HKEY_CURRENT_USER);
+  }
+
+  base::string16 GetEventSubkey() {
+    // There should be a single subkey named after this process' pid.
+    base::win::RegistryKeyIterator it(HKEY_CURRENT_USER, kRegistryPath);
+    EXPECT_EQ(1, it.SubkeyCount());
+
+    unsigned pid = 0;
+    base::StringToUint(it.Name(), &pid);

[erikwright (departed), 2014/12/12 16:58:29]

Is this relying on parsing the string part until a non-digit character and
ignoring the creation time that follows? If so, please document that.

[Sigurður Ásgeirsson, 2014/12/12 20:25:13]

Done.

+    EXPECT_EQ(base::GetCurrentProcId(), pid);
+
+    return it.Name();
+  }
+
+  // TODO(siggi): Reuse the reading code from the metrics provider.
+  EventMap ReadEventsFromSubkey(const base::string16& subkey_name) {
+    base::string16 key_name(
+        base::StringPrintf(L"%ls\\%ls", kRegistryPath, subkey_name.c_str()));
+
+    base::win::RegKey key(HKEY_CURRENT_USER, key_name.c_str(), KEY_READ);
+    EXPECT_TRUE(key.Valid());
+    EXPECT_EQ(2, key.GetValueCount());
+
+    EventMap events;
+    for (size_t i = 0; i < key.GetValueCount(); ++i) {
+      base::string16 name;
+      EXPECT_EQ(key.GetValueNameAt(i, &name), ERROR_SUCCESS);
+      int64 value = 0;
+      EXPECT_EQ(key.ReadInt64(name.c_str(), &value), ERROR_SUCCESS);
+
+      events[name] = value;
+    }
+
+    return events;
+  }
+
+  EventMap ReadEvents() {
+    base::string16 name = GetEventSubkey();
+    return ReadEventsFromSubkey(name);
+  }
+
+ protected:
+  registry_util::RegistryOverrideManager override_manager_;
+};
+
+}  // namespace
+
+TEST_F(ExitFunnelWinTest, RecordSingleEvent) {
+  // Record a couple of events.
+  ASSERT_TRUE(ExitFunnel::RecordSingleEvent(kRegistryPath, L"One"));
+  ASSERT_TRUE(ExitFunnel::RecordSingleEvent(kRegistryPath, L"Two"));
+
+  EventMap events = ReadEvents();
+
+  ASSERT_EQ(events.size(), 2);
+  ASSERT_TRUE(events.find(L"One") != events.end());
+  ASSERT_TRUE(events.find(L"Two") != events.end());
+}
+
+TEST_F(ExitFunnelWinTest, RecordsEventTimes) {
+  ExitFunnel funnel;
+
+  ASSERT_TRUE(funnel.Init(kRegistryPath, base::GetCurrentProcessHandle()));
+  ASSERT_TRUE(funnel.RecordEvent(L"One"));
+
+  // Sleep for half a second to space the events in time.
+  base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(500));

[erikwright (departed), 2014/12/12 16:58:29]

Is there any reason to make this much more than the resolution of
base::Time::Now()? I would reduce this to 50ms to reduce the impact on test
execution times.

[Sigurður Ásgeirsson, 2014/12/12 20:25:13]

Done.

+
+  ASSERT_TRUE(funnel.RecordEvent(L"Two"));
+
+  EventMap events = ReadEvents();
+  ASSERT_EQ(events.size(), 2);
+
+  base::TimeDelta one = base::TimeDelta::FromInternalValue(events[L"One"]);
+  base::TimeDelta two = base::TimeDelta::FromInternalValue(events[L"Two"]);
+
+  // Sleep is not accurate, it may over or under sleep. To minimize flakes,
+  // this test only compares relative ordering of the events.
+  ASSERT_LT(one, two);
+}
+
+}  // namespace browser_watcher