Add SyncScheduler for scheduling CryptAuth enrollments and syncing devices.

components/proximity_auth/cryptauth/sync_scheduler_impl_unittest.cc

+// Copyright 2015 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/proximity_auth/cryptauth/sync_scheduler_impl.h"
+
+#include "base/timer/mock_timer.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace proximity_auth {
+
+using Strategy = SyncScheduler::Strategy;
+using SyncState = SyncScheduler::SyncState;
+
+namespace {
+
+// Constants configuring the the scheduler.
+const int kElapsedTimeDays = 40;
+const int kRefreshPeriodDays = 30;
+const int kRecoveryPeriodSeconds = 10;
+const double kMaxJitterPercentage = 0.1;
+const char kTestSchedulerName[] = "TestSyncSchedulerImpl";
+
+// Returns true if |jittered_time_delta| is within the range of a jittered
+// |base_time_delta| with a maximum of |max_jitter_ratio|.
+bool IsTimeDeltaWithinJitter(const base::TimeDelta& base_time_delta,
+                             const base::TimeDelta& jittered_time_delta,
+                             double max_jitter_ratio) {
+  if (base_time_delta.is_zero())
+    return jittered_time_delta.is_zero();
+
+  base::TimeDelta difference =
+      (jittered_time_delta - base_time_delta).magnitude();
+  double percentage_of_base =
+      difference.InMillisecondsF() / base_time_delta.InMillisecondsF();
+  return percentage_of_base < max_jitter_ratio;
+}
+
+// Test harness for the SyncSchedulerImpl to create MockTimers.
+class TestSyncSchedulerImpl : public SyncSchedulerImpl {
+ public:
+  TestSyncSchedulerImpl(Delegate* delegate,
+                        base::TimeDelta refresh_period,
+                        base::TimeDelta recovery_period,
+                        double max_jitter_ratio)
+      : SyncSchedulerImpl(delegate,
+                          refresh_period,
+                          recovery_period,
+                          max_jitter_ratio,
+                          kTestSchedulerName) {}
+
+  ~TestSyncSchedulerImpl() override {}
+
+  base::MockTimer* timer() { return mock_timer_; }
+
+ private:
+  scoped_ptr<base::Timer> CreateTimer() override {
+    bool retain_user_task = false;
+    bool is_repeating = false;
+    mock_timer_ = new base::MockTimer(retain_user_task, is_repeating);
+    return make_scoped_ptr(mock_timer_);
+  }
+
+  // A timer instance for testing. Owned by the parent scheduler.
+  base::MockTimer* mock_timer_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestSyncSchedulerImpl);
+};
+
+}  // namespace
+
+class ProximityAuthSyncSchedulerImplTest : public testing::Test,
+                                           public SyncSchedulerImpl::Delegate {
+ protected:
+  ProximityAuthSyncSchedulerImplTest()
+      : refresh_period_(base::TimeDelta::FromDays(kRefreshPeriodDays)),
+        base_recovery_period_(
+            base::TimeDelta::FromSeconds(kRecoveryPeriodSeconds)),
+        zero_elapsed_time_(base::TimeDelta::FromSeconds(0)),
+        scheduler_(new TestSyncSchedulerImpl(this,
+                                             refresh_period_,
+                                             base_recovery_period_,
+                                             0)) {}
+
+  ~ProximityAuthSyncSchedulerImplTest() override {}
+
+  void OnSyncRequested(
+      scoped_ptr<SyncScheduler::SyncRequest> sync_request) override {
+    sync_request_ = sync_request.Pass();
+  }
+
+  base::MockTimer* timer() { return scheduler_->timer(); }
+
+  // The time deltas used to configure |scheduler_|.
+  base::TimeDelta refresh_period_;
+  base::TimeDelta base_recovery_period_;
+  base::TimeDelta zero_elapsed_time_;
+
+  // The scheduler instance under test.
+  scoped_ptr<TestSyncSchedulerImpl> scheduler_;
+
+  scoped_ptr<SyncScheduler::SyncRequest> sync_request_;
+
+  DISALLOW_COPY_AND_ASSIGN(ProximityAuthSyncSchedulerImplTest);
+};
+
+TEST_F(ProximityAuthSyncSchedulerImplTest, ForceSyncSuccess) {
+  scheduler_->Start(zero_elapsed_time_, Strategy::PERIODIC_REFRESH);
+  EXPECT_EQ(Strategy::PERIODIC_REFRESH, scheduler_->GetStrategy());
+  EXPECT_EQ(SyncState::WAITING_FOR_REFRESH, scheduler_->GetSyncState());
+
+  scheduler_->ForceSync();
+  EXPECT_EQ(SyncState::SYNC_IN_PROGRESS, scheduler_->GetSyncState());
+  EXPECT_TRUE(sync_request_);
+  sync_request_->OnDidComplete(true);
+  EXPECT_EQ(Strategy::PERIODIC_REFRESH, scheduler_->GetStrategy());
+  EXPECT_EQ(SyncState::WAITING_FOR_REFRESH, scheduler_->GetSyncState());
+}
+
+TEST_F(ProximityAuthSyncSchedulerImplTest, ForceSyncFailure) {
+  scheduler_->Start(zero_elapsed_time_, Strategy::PERIODIC_REFRESH);
+  EXPECT_EQ(Strategy::PERIODIC_REFRESH, scheduler_->GetStrategy());
+
+  scheduler_->ForceSync();
+  EXPECT_TRUE(sync_request_);
+  sync_request_->OnDidComplete(false);
+  EXPECT_EQ(Strategy::AGGRESSIVE_RECOVERY, scheduler_->GetStrategy());
+}
+
+TEST_F(ProximityAuthSyncSchedulerImplTest, PeriodicRefreshSuccess) {
+  EXPECT_EQ(SyncState::NOT_STARTED, scheduler_->GetSyncState());
+  scheduler_->Start(zero_elapsed_time_, Strategy::PERIODIC_REFRESH);
+  EXPECT_EQ(Strategy::PERIODIC_REFRESH, scheduler_->GetStrategy());
+
+  EXPECT_EQ(refresh_period_, timer()->GetCurrentDelay());
+  timer()->Fire();
+  EXPECT_EQ(SyncState::SYNC_IN_PROGRESS, scheduler_->GetSyncState());
+  ASSERT_TRUE(sync_request_.get());
+
+  sync_request_->OnDidComplete(true);
+  EXPECT_EQ(SyncState::WAITING_FOR_REFRESH, scheduler_->GetSyncState());
+  EXPECT_EQ(Strategy::PERIODIC_REFRESH, scheduler_->GetStrategy());
+}
+
+TEST_F(ProximityAuthSyncSchedulerImplTest, PeriodicRefreshFailure) {
+  scheduler_->Start(zero_elapsed_time_, Strategy::PERIODIC_REFRESH);
+  EXPECT_EQ(Strategy::PERIODIC_REFRESH, scheduler_->GetStrategy());
+  timer()->Fire();
+  sync_request_->OnDidComplete(false);
+  EXPECT_EQ(Strategy::AGGRESSIVE_RECOVERY, scheduler_->GetStrategy());
+}
+
+TEST_F(ProximityAuthSyncSchedulerImplTest, AggressiveRecoverySuccess) {
+  scheduler_->Start(zero_elapsed_time_, Strategy::AGGRESSIVE_RECOVERY);
+  EXPECT_EQ(Strategy::AGGRESSIVE_RECOVERY, scheduler_->GetStrategy());
+
+  EXPECT_EQ(base_recovery_period_, timer()->GetCurrentDelay());
+  timer()->Fire();
+  EXPECT_EQ(SyncState::SYNC_IN_PROGRESS, scheduler_->GetSyncState());
+  ASSERT_TRUE(sync_request_.get());
+
+  sync_request_->OnDidComplete(true);
+  EXPECT_EQ(SyncState::WAITING_FOR_REFRESH, scheduler_->GetSyncState());
+  EXPECT_EQ(Strategy::PERIODIC_REFRESH, scheduler_->GetStrategy());
+}
+
+TEST_F(ProximityAuthSyncSchedulerImplTest, AggressiveRecoveryFailure) {
+  scheduler_->Start(zero_elapsed_time_, Strategy::AGGRESSIVE_RECOVERY);
+
+  timer()->Fire();
+  sync_request_->OnDidComplete(false);
+  EXPECT_EQ(Strategy::AGGRESSIVE_RECOVERY, scheduler_->GetStrategy());
+}
+
+TEST_F(ProximityAuthSyncSchedulerImplTest, AggressiveRecoveryBackOff) {
+  scheduler_->Start(zero_elapsed_time_, Strategy::AGGRESSIVE_RECOVERY);
+  base::TimeDelta last_recovery_period = base::TimeDelta::FromSeconds(0);
+
+  for (int i = 0; i < 20; ++i) {
+    timer()->Fire();
+    EXPECT_EQ(SyncState::SYNC_IN_PROGRESS, scheduler_->GetSyncState());
+    sync_request_->OnDidComplete(false);
+    EXPECT_EQ(Strategy::AGGRESSIVE_RECOVERY, scheduler_->GetStrategy());
+    EXPECT_EQ(SyncState::WAITING_FOR_REFRESH, scheduler_->GetSyncState());
+
+    base::TimeDelta recovery_period = scheduler_->GetTimeToNextSync();
+    EXPECT_LE(last_recovery_period, recovery_period);
+    last_recovery_period = recovery_period;
+  }
+
+  // Backoffs should rapidly converge to the normal refresh period.
+  EXPECT_EQ(refresh_period_, last_recovery_period);
+}
+
+TEST_F(ProximityAuthSyncSchedulerImplTest, RefreshFailureRecoverySuccess) {
+  scheduler_->Start(zero_elapsed_time_, Strategy::PERIODIC_REFRESH);
+  EXPECT_EQ(Strategy::PERIODIC_REFRESH, scheduler_->GetStrategy());
+
+  timer()->Fire();
+  sync_request_->OnDidComplete(false);
+  EXPECT_EQ(Strategy::AGGRESSIVE_RECOVERY, scheduler_->GetStrategy());
+
+  timer()->Fire();
+  sync_request_->OnDidComplete(true);
+  EXPECT_EQ(Strategy::PERIODIC_REFRESH, scheduler_->GetStrategy());
+}
+
+TEST_F(ProximityAuthSyncSchedulerImplTest, SyncImmediatelyForPeriodicRefresh) {
+  scheduler_->Start(base::TimeDelta::FromDays(kElapsedTimeDays),
+                    Strategy::PERIODIC_REFRESH);
+  EXPECT_TRUE(scheduler_->GetTimeToNextSync().is_zero());
+  EXPECT_TRUE(timer()->GetCurrentDelay().is_zero());
+  timer()->Fire();
+  EXPECT_TRUE(sync_request_);
+
+  EXPECT_EQ(Strategy::PERIODIC_REFRESH, scheduler_->GetStrategy());
+}
+
+TEST_F(ProximityAuthSyncSchedulerImplTest,
+       SyncImmediatelyForAggressiveRecovery) {
+  scheduler_->Start(base::TimeDelta::FromDays(kElapsedTimeDays),
+                    Strategy::AGGRESSIVE_RECOVERY);
+  EXPECT_TRUE(scheduler_->GetTimeToNextSync().is_zero());
+  EXPECT_TRUE(timer()->GetCurrentDelay().is_zero());
+  timer()->Fire();
+  EXPECT_TRUE(sync_request_);
+
+  EXPECT_EQ(Strategy::AGGRESSIVE_RECOVERY, scheduler_->GetStrategy());
+}
+
+TEST_F(ProximityAuthSyncSchedulerImplTest, InitialSyncShorterByElapsedTime) {
+  base::TimeDelta elapsed_time = base::TimeDelta::FromDays(2);
+  scheduler_->Start(elapsed_time, Strategy::PERIODIC_REFRESH);
+  EXPECT_EQ(refresh_period_ - elapsed_time, scheduler_->GetTimeToNextSync());
+  timer()->Fire();
+  EXPECT_TRUE(sync_request_);
+}
+
+TEST_F(ProximityAuthSyncSchedulerImplTest, PeriodicRefreshJitter) {
+  scheduler_.reset(new TestSyncSchedulerImpl(
+      this, refresh_period_, base_recovery_period_, kMaxJitterPercentage));
+
+  scheduler_->Start(zero_elapsed_time_, Strategy::PERIODIC_REFRESH);
+
+  base::TimeDelta cumulative_jitter = base::TimeDelta::FromSeconds(0);
+  for (int i = 0; i < 10; ++i) {
+    base::TimeDelta next_sync_delta = scheduler_->GetTimeToNextSync();
+    cumulative_jitter += (next_sync_delta - refresh_period_).magnitude();
+    EXPECT_TRUE(IsTimeDeltaWithinJitter(refresh_period_, next_sync_delta,
+                                        kMaxJitterPercentage));
+    timer()->Fire();
+    sync_request_->OnDidComplete(true);
+  }
+
+  // The probablility that all periods are randomly equal to |refresh_period_|
+  // is so low that we would expect the heat death of the universe before this
+  // test flakes.
+  EXPECT_FALSE(cumulative_jitter.is_zero());
+}
+
+TEST_F(ProximityAuthSyncSchedulerImplTest, JitteredTimeDeltaIsNonNegative) {
+  base::TimeDelta zero_delta = base::TimeDelta::FromSeconds(0);
+  double max_jitter_ratio = 1;
+  scheduler_.reset(new TestSyncSchedulerImpl(this, zero_delta, zero_delta,
+                                             max_jitter_ratio));
+  scheduler_->Start(zero_elapsed_time_, Strategy::PERIODIC_REFRESH);
+
+  for (int i = 0; i < 10; ++i) {
+    base::TimeDelta next_sync_delta = scheduler_->GetTimeToNextSync();
+    EXPECT_GE(zero_delta, next_sync_delta);
+    EXPECT_TRUE(
+        IsTimeDeltaWithinJitter(zero_delta, next_sync_delta, max_jitter_ratio));
+    timer()->Fire();
+    sync_request_->OnDidComplete(true);
+  }
+}
+
+}  // namespace proximity_auth