Add policy for limiting the session length

chrome/browser/chromeos/power/session_length_limiter_unittest.cc

Index: chrome/browser/chromeos/power/session_length_limiter_unittest.cc
diff --git a/chrome/browser/chromeos/power/session_length_limiter_unittest.cc b/chrome/browser/chromeos/power/session_length_limiter_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c2b778dd890e46bcd7574b003b90ade932a90f16
--- /dev/null
+++ b/chrome/browser/chromeos/power/session_length_limiter_unittest.cc
@@ -0,0 +1,384 @@
+// Copyright (c) 2012 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/chromeos/power/session_length_limiter.h"
+
+#include <deque>
+#include <utility>
+
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/single_thread_task_runner.h"
+#include "base/string_number_conversions.h"
+#include "base/thread_task_runner_handle.h"
+#include "base/time.h"
+#include "base/values.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/common/pref_names.h"
+#include "chrome/test/base/testing_browser_process.h"
+#include "chrome/test/base/testing_pref_service.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using ::testing::_;
+using ::testing::Invoke;
+using ::testing::Mock;
+using ::testing::NiceMock;
+
+namespace chromeos {
+
+namespace {
+
+// The interval at which the SessionLengthLimiter checks whether the remaining
+// session time has reachzed zero.
+const base::TimeDelta kSessionLengthLimitTimerInterval(
+    base::TimeDelta::FromSeconds(1));
+
+const base::TimeDelta kZeroTimeDelta;
+const base::TimeDelta kTenSeconds(base::TimeDelta::FromSeconds(10));
+
+class MockSessionLengthLimiterDelegate : public SessionLengthLimiter::Delegate {
+ public:
+  MOCK_CONST_METHOD0(GetCurrentTime, const base::Time(void));
+  MOCK_METHOD0(StopSession, void(void));
+};
+
+// A SingleThreadTaskRunner that allows the task queue to be inspected and
+// delayed tasks to be run without waiting for the actual delays to expire.
+class ImmediateSingleThreadTaskRunner : public base::SingleThreadTaskRunner {
+ public:
+  virtual bool RunsTasksOnCurrentThread() const OVERRIDE {
+    return true;
+  }
+
+  virtual bool PostDelayedTask(const tracked_objects::Location& from_here,
+                               const base::Closure& task,
+                               base::TimeDelta delay) OVERRIDE {
+    tasks_.push_back(std::pair<base::TimeDelta, base::Closure>(delay, task));
+    return true;
+  }
+
+  virtual bool PostNonNestableDelayedTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task,
+      base::TimeDelta delay) OVERRIDE {
+    NOTREACHED();
+    return false;
+  }
+
+  void RunTasks() {
+    std::deque<std::pair<base::TimeDelta, base::Closure> > tasks;
+    tasks.swap(tasks_);
+    for (std::deque<std::pair<base::TimeDelta, base::Closure> >::iterator
+             it = tasks.begin(); it != tasks.end(); ++it) {
+      it->second.Run();
+    }
+  }
+
+  const std::deque<std::pair<base::TimeDelta, base::Closure> >& tasks() const {
+    return tasks_;
+  }
+
+ private:
+  std::deque<std::pair<base::TimeDelta, base::Closure> > tasks_;
+
+  virtual ~ImmediateSingleThreadTaskRunner() {}
+};
+
+}  // namespace
+
+class SessionLengthLimiterTest : public testing::Test {
+ protected:
+  SessionLengthLimiterTest() : delegate_(NULL) {
+  }
+
+  virtual void SetUp() {
+    static_cast<TestingBrowserProcess*>(g_browser_process)->
+        SetLocalState(&local_state_);
+    SessionLengthLimiter::RegisterPrefs(&local_state_);
+
+    delegate_ = new NiceMock<MockSessionLengthLimiterDelegate>;
+    ON_CALL(*delegate_, GetCurrentTime())
+        .WillByDefault(Invoke(this, &SessionLengthLimiterTest::GetCurrentTime));
+    EXPECT_CALL(*delegate_, StopSession()).Times(0);
+    runner_ = new ImmediateSingleThreadTaskRunner;
+
+    // Initialize the mock clock to a fixed value, ensuring that timezone
+    // differences or DST changes do not affect the test.
+    now_ = base::Time::UnixEpoch() + base::TimeDelta::FromDays(40 * 365);
+    session_start_time_ = now_;
+  }
+
+  virtual void TearDown() {
+    static_cast<TestingBrowserProcess*>(g_browser_process)->SetLocalState(NULL);
+  }
+
+  void SetSessionStartTimePref(int64 session_start_time) {
+    local_state_.SetUserPref(prefs::kSessionStartTime,
+                             base::Value::CreateStringValue(
+                                 base::Int64ToString(session_start_time)));
+  }
+
+  void VerifySessionStartTimePref() {
+    base::Time session_start_time(base::Time::FromInternalValue(
+        local_state_.GetInt64(prefs::kSessionStartTime)));
+    EXPECT_EQ(session_start_time_, session_start_time);
+  }
+
+  void SetSessionLengthLimitPref(int64 session_length_limit) {
+    local_state_.SetUserPref(prefs::kSessionLengthLimit,
+                             base::Value::CreateIntegerValue(
+                                 session_length_limit));
+    base::TimeDelta remaining(
+          base::TimeDelta::FromMilliseconds(session_length_limit) -
+              (now_ - session_start_time_));
+      if (remaining < kZeroTimeDelta)
+        remaining = kZeroTimeDelta;
+    remaining_.reset(new base::TimeDelta(remaining));
+  }
+
+  void ExpectStopSession() {
+    Mock::VerifyAndClearExpectations(delegate_);
+    EXPECT_CALL(*delegate_, StopSession()).Times(1);
+  }
+
+  void CreateSessionLengthLimiter(bool browser_restarted) {
+    session_length_limiter_.reset(
+        new SessionLengthLimiter(delegate_, browser_restarted));
+  }
+
+  void VerifyNoTimerTickIsEnqueued() {
+    EXPECT_TRUE(runner_->tasks().empty());
+  }
+
+  void VerifyTimerTickIsEnqueued() {
+    ASSERT_EQ(1U, runner_->tasks().size());
+    EXPECT_EQ(kSessionLengthLimitTimerInterval,
+              runner_->tasks().front().first);
+  }
+
+  void VerifyTimerTick() {
+    VerifyTimerTickIsEnqueued();
+    runner_->RunTasks();
+
+    now_ += kSessionLengthLimitTimerInterval;
+    *remaining_ -= kSessionLengthLimitTimerInterval;
+    if (*remaining_ < kZeroTimeDelta)
+      remaining_.reset(new base::TimeDelta(kZeroTimeDelta));
+  }
+
+  base::Time GetCurrentTime() const {
+    return now_;
+  }
+
+  TestingPrefService local_state_;
+  MockSessionLengthLimiterDelegate* delegate_;  // Owned by
+                                                // session_length_limiter_.
+  scoped_refptr<ImmediateSingleThreadTaskRunner> runner_;
+
+  base::Time session_start_time_;
+  base::Time now_;
+  scoped_ptr<base::TimeDelta> remaining_;
+
+  scoped_ptr<SessionLengthLimiter> session_length_limiter_;
+};
+
+// Verifies that the session start time in local state is updated during login
+// if no session start time has been stored before.
+TEST_F(SessionLengthLimiterTest, StartWithSessionStartTimeUnset) {
+  CreateSessionLengthLimiter(false);
+  VerifySessionStartTimePref();
+}
+
+// Verifies that the session start time in local state is updated during login
+// if an invalid session start time has been stored before.
+TEST_F(SessionLengthLimiterTest, StartWithSessionStartTimeInvalid) {
+  SetSessionStartTimePref(0);
+  CreateSessionLengthLimiter(false);
+  VerifySessionStartTimePref();
+}
+
+// Verifies that the session start time in local state is updated during login
+// if a session start time lying in the future has been stored before.
+TEST_F(SessionLengthLimiterTest, StartWithSessionStartTimeFuture) {
+  SetSessionStartTimePref(
+      (now_ + base::TimeDelta::FromHours(2)).ToInternalValue());
+  CreateSessionLengthLimiter(false);
+  VerifySessionStartTimePref();
+}
+
+// Verifies that the session start time in local state is updated during login
+// if a valid session start time has been stored before.
+TEST_F(SessionLengthLimiterTest, StartWithSessionStartTimeValid) {
+  const base::Time previous_start_time = now_ - base::TimeDelta::FromHours(2);
+  SetSessionStartTimePref(previous_start_time.ToInternalValue());
+  CreateSessionLengthLimiter(false);
+  VerifySessionStartTimePref();
+}
+
+// Verifies that the session start time in local state is updated during restart
+// after a crash if no session start time has been stored before.
+TEST_F(SessionLengthLimiterTest, RestartWithSessionStartTimeUnset) {
+  CreateSessionLengthLimiter(true);
+  VerifySessionStartTimePref();
+}
+
+// Verifies that the session start time in local state is updated during restart
+// after a crash if an invalid session start time has been stored before.
+TEST_F(SessionLengthLimiterTest, RestartWithSessionStartTimeInvalid) {
+  SetSessionStartTimePref(0);
+  CreateSessionLengthLimiter(true);
+  VerifySessionStartTimePref();
+}
+
+// Verifies that the session start time in local state is updated during restart
+// after a crash if a session start time lying in the future has been stored
+// before.
+TEST_F(SessionLengthLimiterTest, RestartWithSessionStartTimeFuture) {
+  SetSessionStartTimePref(
+      (now_ + base::TimeDelta::FromHours(2)).ToInternalValue());
+  CreateSessionLengthLimiter(true);
+  VerifySessionStartTimePref();
+}
+
+// Verifies that the session start time in local state is *not* updated during
+// restart after a crash if a valid session start time has been stored before.
+TEST_F(SessionLengthLimiterTest, RestartWithSessionStartTimeValid) {
+  session_start_time_ -= base::TimeDelta::FromHours(2);
+  SetSessionStartTimePref(session_start_time_.ToInternalValue());
+  CreateSessionLengthLimiter(true);
+  VerifySessionStartTimePref();
+}
+
+// Creates a SessionLengthLimiter without setting a limit. Verifies that the
+// limiter does not start a timer.
+TEST_F(SessionLengthLimiterTest, RunWithoutSessionLengthLimit) {
+  base::ThreadTaskRunnerHandle runner_handler(runner_);
+
+  // Create a SessionLengthLimiter.
+  CreateSessionLengthLimiter(false);
+
+  // Verify that no timer tick has been enqueued.
+  VerifyNoTimerTickIsEnqueued();
+}
+
+// Creates a SessionLengthLimiter after setting a limit. Verifies that the
+// limiter starts a timer and that when the session length reaches the limit,
+// the session is terminated.
+TEST_F(SessionLengthLimiterTest, RunWithSessionLengthLimit) {
+  base::ThreadTaskRunnerHandle runner_handler(runner_);
+
+  // Set a 60 second session time limit.
+  SetSessionLengthLimitPref(60 * 1000);  // 60 seconds.
+
+  // Create a SessionLengthLimiter.
+  CreateSessionLengthLimiter(false);
+
+  // Check timer ticks until the remaining session time reaches zero.
+  while (*remaining_ > kZeroTimeDelta)
+    VerifyTimerTick();
+
+  // Check that the next timer tick leads to the session being terminated.
+  ExpectStopSession();
+  VerifyTimerTick();
+}
+
+// Creates a SessionLengthLimiter after setting a 60 second limit, allows 50
+// seconds of session time to pass, then increases the limit to 90 seconds.
+// Verifies that when the session time reaches the new 90 second limit, the
+// session is terminated.
+TEST_F(SessionLengthLimiterTest, RunAndIncreaseSessionLengthLimit) {
+  base::ThreadTaskRunnerHandle runner_handler(runner_);
+
+  // Set a 60 second session time limit.
+  SetSessionLengthLimitPref(60 * 1000);  // 60 seconds.
+
+  // Create a SessionLengthLimiter.
+  CreateSessionLengthLimiter(false);
+
+  // Check timer ticks for 50 seconds of session time.
+  while (*remaining_ > kTenSeconds)
+    VerifyTimerTick();
+
+  // Increase the session length limit to 90 seconds.
+  SetSessionLengthLimitPref(90 * 1000);  // 90 seconds.
+
+  // Check timer ticks until the remaining session time reaches zero.
+  while (*remaining_  > kZeroTimeDelta)
+    VerifyTimerTick();
+
+  // Check that the next timer tick leads to the session being terminated.
+  ExpectStopSession();
+  VerifyTimerTick();
+}
+
+// Creates a SessionLengthLimiter after setting a 60 second limit, allows 50
+// seconds of session time to pass, then decreases the limit to 40 seconds.
+// Verifies that when the limit is decreased to 40 seconds after 50 seconds of
+// session time have passed, the next timer tick causes the session to be
+// terminated.
+TEST_F(SessionLengthLimiterTest, RunAndDecreaseSessionLengthLimit) {
+  base::ThreadTaskRunnerHandle runner_handler(runner_);
+
+  // Set a 60 second session time limit.
+  SetSessionLengthLimitPref(60 * 1000);  // 60 seconds.
+
+  // Create a SessionLengthLimiter.
+  CreateSessionLengthLimiter(false);
+
+  // Check timer ticks for 50 seconds of session time.
+  while (*remaining_ > kTenSeconds)
+    VerifyTimerTick();
+
+  // Reduce the session length limit below the 50 seconds that have already
+  // elapsed.
+  SetSessionLengthLimitPref(40 * 1000);  // 40 seconds.
+
+  // Check that the next timer tick causes the session to be terminated.
+  ExpectStopSession();
+  VerifyTimerTick();
+}
+
+// Creates a SessionLengthLimiter after setting a 60 second limit, allows 50
+// seconds of session time to pass, then removes the limit. Verifies that after
+// the limit is removed, the session is not terminated when the session time
+// reaches the original 60 second limit.
+TEST_F(SessionLengthLimiterTest, RunAndRemoveSessionLengthLimit) {
+  base::ThreadTaskRunnerHandle runner_handler(runner_);
+
+  // Set a 60 second session time limit.
+  SetSessionLengthLimitPref(60 * 1000);  // 60 seconds.
+
+  // Create a SessionLengthLimiter.
+  CreateSessionLengthLimiter(false);
+
+  // Check timer ticks for 50 seconds of session time.
+  while (*remaining_ > kTenSeconds)
+    VerifyTimerTick();
+
+  // Remove the session length limit.
+  local_state_.RemoveUserPref(prefs::kSessionLengthLimit);
+
+  // Continue advancing the session time until it reaches the original 60 second
+  // limit.
+  while (*remaining_ > kZeroTimeDelta) {
+    runner_->RunTasks();
+
+    now_ += kSessionLengthLimitTimerInterval;
+    *remaining_ -= kSessionLengthLimitTimerInterval;
+    if (*remaining_ < kZeroTimeDelta)
+      remaining_.reset(new base::TimeDelta(kZeroTimeDelta));
+  }
+
+  // Check that the next timer tick does not lead to the session being
+  // terminated.
+  now_ += kSessionLengthLimitTimerInterval;
+  runner_->RunTasks();
+}
+
+}  // namespace chromeos