Bound the impact of system instability on chrome instability.

components/browser_watcher/system_session_analyzer_win_unittest.cc

Index: components/browser_watcher/system_session_analyzer_win_unittest.cc
diff --git a/components/browser_watcher/system_session_analyzer_win_unittest.cc b/components/browser_watcher/system_session_analyzer_win_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..22a6416ee29ea7b0a12586dd30c0e5ddd5fcc157
--- /dev/null
+++ b/components/browser_watcher/system_session_analyzer_win_unittest.cc
@@ -0,0 +1,118 @@
+// 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 "components/browser_watcher/system_session_analyzer_win.h"
+
+#include <utility>
+#include <vector>
+
+#include "base/time/time.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace browser_watcher {
+
+// Ensure the fetcher retrieves events. Assumes the test host has at least 1
+// prior session.
+TEST(SystemSessionEventFetcherTest, TestRetrieval) {

[Sigurður Ásgeirsson, 2017/03/01 15:09:27]

mmm - will this fail on every new test bot until it's rebooted?
Maybe add a comment that this might happen for a totally fresh bot?

[manzagop (departed), 2017/03/01 21:07:45]

Yeah, this will happen and will be annoying. I've commented and disabled the
test.

+  SystemSessionEventFetcher fetcher(1);
+
+  std::vector<SystemSessionEventFetcher::EventInfo> events;
+  ASSERT_TRUE(fetcher.FetchEvents(&events));
+  EXPECT_EQ(3U, events.size());
+}
+
+// Ensure the fetcher's retrieved events conform to our expectations. This
+// conformance is validated using the SystemSessionAnalyzer. Note that the
+// ability of SystemSessionAnalyzer to validate the conformance is tested below.
+TEST(SystemSessionEventFetcherTest, NoEvent) {
+  std::unique_ptr<SystemSessionEventFetcher> fetcher(
+      new SystemSessionEventFetcher(1));
+  SystemSessionAnalyzer analyzer(std::move(fetcher));
+  EXPECT_EQ(SystemSessionAnalyzer::CLEAN,
+            analyzer.IsSessionUnclean(base::Time::Now()));
+}
+

[Sigurður Ásgeirsson, 2017/03/01 15:09:27]

In Syzygy we use "Mock"XXX - is there a tradition to use "Fake"XXX?

[manzagop (departed), 2017/03/01 21:07:45]

Actually, this is a stub. Mocks validate interaction, fakes are lightweight
implementations of the real thing and stubs returned canned responses.

Changed to Stub*.

+class FakeSystemSessionEventFetcher : public SystemSessionEventFetcher {
+ public:
+  FakeSystemSessionEventFetcher() : SystemSessionEventFetcher(10U) {}
+
+  bool FetchEvents(std::vector<EventInfo>* event_infos) const override {
+    DCHECK(event_infos);
+    *event_infos = events_;
+    return true;
+  }
+
+  void AddEvent(const EventInfo& info) { events_.push_back(info); }
+
+ private:
+  std::vector<EventInfo> events_;
+};
+
+TEST(SystemSessionAnalyzerTest, StandardCase) {
+  std::unique_ptr<FakeSystemSessionEventFetcher> fetcher(
+      new FakeSystemSessionEventFetcher());
+
+  base::Time time = base::Time::Now();
+  fetcher->AddEvent({6005U, time});

[Sigurður Ásgeirsson, 2017/03/01 15:09:27]

nit: can we have declarative constants for the magic values here?

[manzagop (departed), 2017/03/01 21:07:45]

Done.

+  fetcher->AddEvent({6008U, time - base::TimeDelta::FromSeconds(10)});
+  fetcher->AddEvent({6005U, time - base::TimeDelta::FromSeconds(20)});
+  fetcher->AddEvent({6006U, time - base::TimeDelta::FromSeconds(22)});
+  fetcher->AddEvent({6005U, time - base::TimeDelta::FromSeconds(28)});
+
+  SystemSessionAnalyzer analyzer(std::move(fetcher));
+
+  EXPECT_EQ(SystemSessionAnalyzer::OUTSIDE_RANGE,
+            analyzer.IsSessionUnclean(time - base::TimeDelta::FromSeconds(30)));
+  EXPECT_EQ(SystemSessionAnalyzer::CLEAN,
+            analyzer.IsSessionUnclean(time - base::TimeDelta::FromSeconds(25)));
+  EXPECT_EQ(SystemSessionAnalyzer::UNCLEAN,
+            analyzer.IsSessionUnclean(time - base::TimeDelta::FromSeconds(20)));
+  EXPECT_EQ(SystemSessionAnalyzer::UNCLEAN,
+            analyzer.IsSessionUnclean(time - base::TimeDelta::FromSeconds(15)));
+  EXPECT_EQ(SystemSessionAnalyzer::UNCLEAN,
+            analyzer.IsSessionUnclean(time - base::TimeDelta::FromSeconds(10)));
+  EXPECT_EQ(SystemSessionAnalyzer::CLEAN,
+            analyzer.IsSessionUnclean(time - base::TimeDelta::FromSeconds(5)));
+  EXPECT_EQ(SystemSessionAnalyzer::CLEAN,
+            analyzer.IsSessionUnclean(time + base::TimeDelta::FromSeconds(5)));
+}
+
+TEST(SystemSessionAnalyzerTest, NoEvent) {
+  std::unique_ptr<SystemSessionEventFetcher> fetcher(
+      new FakeSystemSessionEventFetcher());
+  SystemSessionAnalyzer analyzer(std::move(fetcher));
+  EXPECT_EQ(SystemSessionAnalyzer::FAILED,
+            analyzer.IsSessionUnclean(base::Time::Now()));
+}
+
+TEST(SystemSessionAnalyzerTest, TimeInversion) {
+  std::unique_ptr<FakeSystemSessionEventFetcher> fetcher(
+      new FakeSystemSessionEventFetcher());
+
+  base::Time time = base::Time::Now();
+  fetcher->AddEvent({6005U, time});
+  fetcher->AddEvent({6006U, time + base::TimeDelta::FromSeconds(1)});
+  fetcher->AddEvent({6005U, time - base::TimeDelta::FromSeconds(1)});
+
+  SystemSessionAnalyzer analyzer(std::move(fetcher));
+  EXPECT_EQ(SystemSessionAnalyzer::FAILED,
+            analyzer.IsSessionUnclean(base::Time::Now()));
+}
+
+TEST(SystemSessionAnalyzerTest, IdInversion) {
+  std::unique_ptr<FakeSystemSessionEventFetcher> fetcher(
+      new FakeSystemSessionEventFetcher());
+
+  base::Time time = base::Time::Now();
+  fetcher->AddEvent({6005U, time});
+  fetcher->AddEvent({6005U, time - base::TimeDelta::FromSeconds(1)});
+  fetcher->AddEvent({6006U, time - base::TimeDelta::FromSeconds(2)});
+
+  SystemSessionAnalyzer analyzer(std::move(fetcher));
+  EXPECT_EQ(SystemSessionAnalyzer::FAILED,
+            analyzer.IsSessionUnclean(base::Time::Now()));
+}
+
+}  // namespace browser_watcher