Implement throttling logic for fetching affiliation information.

components/password_manager/core/browser/affiliation_fetch_throttler_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/password_manager/core/browser/affiliation_fetch_throttler.h"
+
+#include <cmath>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/numerics/safe_math.h"
+#include "base/run_loop.h"
+#include "base/test/test_mock_time_task_runner.h"
+#include "base/thread_task_runner_handle.h"
+#include "base/time/tick_clock.h"
+#include "base/time/time.h"
+#include "components/password_manager/core/browser/affiliation_fetch_throttler_delegate.h"
+#include "net/base/network_change_notifier.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace password_manager {
+namespace {
+
+class MockAffiliationFetchThrottlerDelegate
+    : public AffiliationFetchThrottlerDelegate {
+ public:
+  MockAffiliationFetchThrottlerDelegate(scoped_ptr<base::TickClock> tick_clock)

[mmenke, 2015/01/30 19:50:41]

nit:  explicit

[engedy, 2015/01/30 20:23:13]

Done.

+      : tick_clock_(tick_clock.Pass()),
+        emulated_return_value_(true),
+        release_count_(0u) {}
+  ~MockAffiliationFetchThrottlerDelegate() { EXPECT_EQ(0u, release_count_); }
+
+  void set_emulated_return_value(bool value) { emulated_return_value_ = value; }
+  void reset_release_count() { release_count_ = 0u; }

[mmenke, 2015/01/30 19:50:41]

optional:  Think this variable name is a little unclear.  Suggest either a
comment or replacing release with can_send or just send in the two variable
names that use it.

[engedy, 2015/01/30 20:23:13]

Done.

+  size_t release_count() const { return release_count_; }
+  base::TimeTicks last_release_time() const { return last_release_time_; }
+
+  // AffiliationFetchThrottlerDelegate:
+  bool OnCanSendNetworkRequest() override {
+    ++release_count_;
+    last_release_time_ = tick_clock_->NowTicks();
+    return emulated_return_value_;
+  }
+
+ private:
+  scoped_ptr<base::TickClock> tick_clock_;
+  bool emulated_return_value_;
+  size_t release_count_;
+  base::TimeTicks last_release_time_;
+
+  DISALLOW_COPY_AND_ASSIGN(MockAffiliationFetchThrottlerDelegate);
+};
+
+}  // namespace
+
+class AffiliationFetchThrottlerTest : public testing::Test {
+ public:
+  AffiliationFetchThrottlerTest()
+      : network_change_notifier_(net::NetworkChangeNotifier::CreateMock()),
+        task_runner_(new base::TestMockTimeTaskRunner),
+        mock_delegate_(task_runner_->GetMockTickClock()) {}
+  ~AffiliationFetchThrottlerTest() override {}
+
+  scoped_ptr<AffiliationFetchThrottler> CreateThrottler() {
+    return make_scoped_ptr(new AffiliationFetchThrottler(
+        &mock_delegate_, task_runner_, task_runner_->GetMockTickClock()));
+  }
+
+  void SimulateHasNetworkConnectivity(bool has_connectivity) {
+    net::NetworkChangeNotifier::NotifyObserversOfConnectionTypeChangeForTests(
+        has_connectivity ? net::NetworkChangeNotifier::CONNECTION_UNKNOWN
+                         : net::NetworkChangeNotifier::CONNECTION_NONE);
+    base::RunLoop().RunUntilIdle();
+  }
+
+  // Runs the task runner until no tasks remain, and asserts that by this time,
+  // OnCanSendNetworkRequest() will have been called exactly once, with a delay
+  // between |min_delay_ms| and |max_delay_ms|, modulo 0.5 ms to allow for
+  // floating point errors. When OnCanSendNetworkRequest() is called, the mock
+  // will return |emulated_return_value|. This value normally indicates whether
+  // or not a request was actually issued in response to the call.
+  void AssertReleaseInBetween(bool emulated_return_value,
+                              double min_delay_ms,
+                              double max_delay_ms) {
+    ASSERT_EQ(0u, mock_delegate_.release_count());
+    base::TimeTicks ticks_at_start = task_runner_->GetCurrentMockTime();
+    mock_delegate_.set_emulated_return_value(emulated_return_value);
+    task_runner_->FastForwardUntilNoTasksRemain();
+    ASSERT_EQ(1u, mock_delegate_.release_count());
+    base::TimeDelta delay = mock_delegate_.last_release_time() - ticks_at_start;
+    EXPECT_LE(min_delay_ms - 1, delay.InMillisecondsF());
+    EXPECT_GE(max_delay_ms + 1, delay.InMillisecondsF());
+    mock_delegate_.reset_release_count();
+  }
+
+  // Runs the task runner for |secs| and asserts that OnCanSendNetworkRequest()
+  // will not have been called by the end of this period.
+  void AssertNoReleaseForSecs(int64_t secs) {
+    task_runner_->FastForwardBy(base::TimeDelta::FromSeconds(secs));
+    ASSERT_EQ(0u, mock_delegate_.release_count());
+  }
+
+  // Runs the task runner until no tasks remain, and asserts that
+  // OnCanSendNetworkRequest() will not have been called.
+  void AssertNoReleaseUntilNoTasksRemain() {
+    task_runner_->FastForwardUntilNoTasksRemain();
+    ASSERT_EQ(0u, mock_delegate_.release_count());
+  }
+
+  size_t GetPendingTaskCount() const {
+    return task_runner_->GetPendingTaskCount();
+  }
+
+ private:
+  // Needed because NetworkChangeNotifier uses ObserverList, which notifies
+  // observers on the MessageLoop that belongs to the thread from which they
+  // have registered.
+  base::MessageLoop message_loop_;
+  scoped_ptr<net::NetworkChangeNotifier> network_change_notifier_;
+  scoped_refptr<base::TestMockTimeTaskRunner> task_runner_;
+  MockAffiliationFetchThrottlerDelegate mock_delegate_;
+
+  DISALLOW_COPY_AND_ASSIGN(AffiliationFetchThrottlerTest);
+};
+
+TEST_F(AffiliationFetchThrottlerTest, SuccessfulRequests) {
+  scoped_ptr<AffiliationFetchThrottler> throttler(CreateThrottler());
+
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+
+  // Signal while request is in flight should be ignored.
+  throttler->SignalNetworkRequestNeeded();
+  AssertNoReleaseUntilNoTasksRemain();
+  throttler->InformOfNetworkRequestComplete(true);
+  AssertNoReleaseUntilNoTasksRemain();
+
+  // Duplicate the second signal 3 times: still only 1 callback should arrive.
+  throttler->SignalNetworkRequestNeeded();
+  throttler->SignalNetworkRequestNeeded();
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+}
+
+TEST_F(AffiliationFetchThrottlerTest, FailedRequests) {
+  scoped_ptr<AffiliationFetchThrottler> throttler(CreateThrottler());
+
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+  throttler->InformOfNetworkRequestComplete(false);
+
+  // The request after the first failure should be delayed by |initial_delay_ms|
+  // spread out over Uniform(1 - |jitter_factor|, 1).
+  throttler->SignalNetworkRequestNeeded();
+  const auto& kPolicy = AffiliationFetchThrottler::kBackoffPolicy;
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(
+      true, kPolicy.initial_delay_ms * (1 - kPolicy.jitter_factor),
+      kPolicy.initial_delay_ms));
+  throttler->InformOfNetworkRequestComplete(true);
+
+  // After a successful request, the next one should be released immediately.
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+  throttler->InformOfNetworkRequestComplete(false);
+
+  // In general, the request after the n-th failure should be delayed by
+  //   |multiply_factor| ^ (n-1) * |initial_delay_ms|,
+  // spread out over Uniform(1 - |jitter_factor|, 1), up until
+  //   |maximum_backoff_ms|
+  // is reached.
+  for (size_t num_failures = 1; num_failures < 100; ++num_failures) {
+    throttler->SignalNetworkRequestNeeded();
+    double max_delay_ms = kPolicy.initial_delay_ms *
+                          pow(kPolicy.multiply_factor, num_failures - 1);
+    double min_delay_ms = max_delay_ms * (1 - kPolicy.jitter_factor);
+    if (max_delay_ms > kPolicy.maximum_backoff_ms)
+      max_delay_ms = kPolicy.maximum_backoff_ms;
+    if (min_delay_ms > kPolicy.maximum_backoff_ms)
+      min_delay_ms = kPolicy.maximum_backoff_ms;
+    ASSERT_NO_FATAL_FAILURE(
+        AssertReleaseInBetween(true, min_delay_ms, max_delay_ms));
+    throttler->InformOfNetworkRequestComplete(false);
+  }
+}
+
+TEST_F(AffiliationFetchThrottlerTest, OnCanSendNetworkRequestReturnsFalse) {
+  scoped_ptr<AffiliationFetchThrottler> throttler(CreateThrottler());
+
+  // A need for a network request is signaled, but as OnCanSendNetworkRequest()
+  // is called, the implementation returns false to indicate that the request
+  // will not be needed after all. InformOfNetworkRequestComplete() must not be
+  // called in this case.
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(false, 0, 0));
+
+  // A subsequent signaling, however, should result in OnCanSendNetworkRequest()
+  // being called immediately.
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+}
+
+TEST_F(AffiliationFetchThrottlerTest, GracePeriodAfterConnectivityIsRestored) {
+  scoped_ptr<AffiliationFetchThrottler> throttler(CreateThrottler());
+  SimulateHasNetworkConnectivity(false);
+
+  // After connectivity is restored, the first request should be delayed by the
+  // grace period, spread out over Uniform(1 - |jitter_factor|, 1).
+  throttler->SignalNetworkRequestNeeded();
+  AssertNoReleaseUntilNoTasksRemain();
+
+  SimulateHasNetworkConnectivity(true);
+  const auto& kPolicy = AffiliationFetchThrottler::kBackoffPolicy;
+  const int64_t& kGraceMs =
+      AffiliationFetchThrottler::kGracePeriodAfterReconnectMs;
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(
+      true, kGraceMs * (1 - kPolicy.jitter_factor), kGraceMs));
+  throttler->InformOfNetworkRequestComplete(true);
+
+  // The next request should not be delayed.
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+}
+
+// Same as GracePeriodAfterConnectivityIsRestored, but the network comes back
+// just before SignalNetworkRequestNeeded() is called.
+TEST_F(AffiliationFetchThrottlerTest, GracePeriodAfterConnectivityIsRestored2) {
+  scoped_ptr<AffiliationFetchThrottler> throttler(CreateThrottler());
+  SimulateHasNetworkConnectivity(false);
+
+  SimulateHasNetworkConnectivity(true);
+  throttler->SignalNetworkRequestNeeded();
+  const auto& kPolicy = AffiliationFetchThrottler::kBackoffPolicy;
+  const int64_t& kGraceMs =
+      AffiliationFetchThrottler::kGracePeriodAfterReconnectMs;
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(
+      true, kGraceMs * (1 - kPolicy.jitter_factor), kGraceMs));
+  throttler->InformOfNetworkRequestComplete(true);
+
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+}
+
+TEST_F(AffiliationFetchThrottlerTest, ConnectivityLostDuringBackoff) {
+  scoped_ptr<AffiliationFetchThrottler> throttler(CreateThrottler());
+
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+  throttler->InformOfNetworkRequestComplete(false);
+
+  throttler->SignalNetworkRequestNeeded();
+  SimulateHasNetworkConnectivity(false);
+
+  // Let the exponential backoff delay expire, and verify nothing happens.
+  AssertNoReleaseUntilNoTasksRemain();
+
+  // Verify that the request is, however, sent after the normal grace period
+  // once connectivity is restored.
+  SimulateHasNetworkConnectivity(true);
+  const auto& kPolicy = AffiliationFetchThrottler::kBackoffPolicy;
+  const int64_t& kGraceMs =
+      AffiliationFetchThrottler::kGracePeriodAfterReconnectMs;
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(
+      true, kGraceMs * (1 - kPolicy.jitter_factor), kGraceMs));
+  throttler->InformOfNetworkRequestComplete(true);
+}
+
+TEST_F(AffiliationFetchThrottlerTest,
+       ConnectivityLostAndRestoredDuringBackoff) {
+  scoped_ptr<AffiliationFetchThrottler> throttler(CreateThrottler());
+
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+  throttler->InformOfNetworkRequestComplete(false);
+
+  throttler->SignalNetworkRequestNeeded();
+  const auto& kPolicy = AffiliationFetchThrottler::kBackoffPolicy;
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(
+      true, kPolicy.initial_delay_ms * (1 - kPolicy.jitter_factor),
+      kPolicy.initial_delay_ms));
+  throttler->InformOfNetworkRequestComplete(false);
+
+  SimulateHasNetworkConnectivity(false);
+  SimulateHasNetworkConnectivity(true);
+
+  // This test expects that the exponential backoff interval after the 2nd error
+  // is larger than the normal grace period after connectivity is restored.
+  const int64_t& kGraceMs =
+      AffiliationFetchThrottler::kGracePeriodAfterReconnectMs;
+  EXPECT_PRED_FORMAT2(testing::DoubleLE, kGraceMs,
+                      kPolicy.initial_delay_ms * kPolicy.multiply_factor);
+
+  // The release should come after the longest of the two intervals expire.
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(
+      true, kPolicy.initial_delay_ms * kPolicy.multiply_factor *
+                (1 - kPolicy.jitter_factor),
+      kPolicy.initial_delay_ms * kPolicy.multiply_factor));
+  throttler->InformOfNetworkRequestComplete(false);
+}
+
+TEST_F(AffiliationFetchThrottlerTest, FlakyConnectivity) {
+  scoped_ptr<AffiliationFetchThrottler> throttler(CreateThrottler());
+
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+  throttler->InformOfNetworkRequestComplete(false);
+
+  // Run for a total of 5 grace periods and simulate connectivity being lost and
+  // restored every second. This verifies that a flaky connection will not flood
+  // the task queue with lots of of tasks and also that release will not happen
+  // while the connection is flaky even once the first grace period has expired.
+  throttler->SignalNetworkRequestNeeded();
+  const auto& kPolicy = AffiliationFetchThrottler::kBackoffPolicy;
+  const int64_t& kGraceMs =
+      AffiliationFetchThrottler::kGracePeriodAfterReconnectMs;
+  int64_t five_grace_periods_secs =
+      kGraceMs * 5 / base::Time::kMillisecondsPerSecond;
+  for (int64_t t = 0; t < five_grace_periods_secs; ++t) {
+    SimulateHasNetworkConnectivity(false);
+    AssertNoReleaseForSecs(1);
+    SimulateHasNetworkConnectivity(true);
+    EXPECT_EQ(1u, GetPendingTaskCount());
+  }
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(
+      true, kGraceMs * (1 - kPolicy.jitter_factor), kGraceMs));
+}
+
+TEST_F(AffiliationFetchThrottlerTest, ConnectivityLostDuringRequest) {
+  scoped_ptr<AffiliationFetchThrottler> throttler(CreateThrottler());
+
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+
+  SimulateHasNetworkConnectivity(false);
+  AssertNoReleaseUntilNoTasksRemain();
+  throttler->InformOfNetworkRequestComplete(false);
+  AssertNoReleaseUntilNoTasksRemain();
+  throttler->SignalNetworkRequestNeeded();
+  AssertNoReleaseUntilNoTasksRemain();
+
+  SimulateHasNetworkConnectivity(true);
+
+  // Verify that the next request is released after the normal grace period.
+  const auto& kPolicy = AffiliationFetchThrottler::kBackoffPolicy;
+  const int64_t& kGraceMs =
+      AffiliationFetchThrottler::kGracePeriodAfterReconnectMs;
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(
+      true, kGraceMs * (1 - kPolicy.jitter_factor), kGraceMs));
+  throttler->InformOfNetworkRequestComplete(true);
+}
+
+TEST_F(AffiliationFetchThrottlerTest,
+       ConnectivityLostAndRestoredDuringRequest) {
+  scoped_ptr<AffiliationFetchThrottler> throttler(CreateThrottler());
+
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+
+  SimulateHasNetworkConnectivity(false);
+  AssertNoReleaseUntilNoTasksRemain();
+  SimulateHasNetworkConnectivity(true);
+  AssertNoReleaseUntilNoTasksRemain();
+  throttler->InformOfNetworkRequestComplete(true);
+
+  // Even though the previous request succeeded, the next request should still
+  // be held back for the normal grace period after connection is restored.
+  throttler->SignalNetworkRequestNeeded();
+  const auto& kPolicy = AffiliationFetchThrottler::kBackoffPolicy;
+  const int64_t& kGraceMs =
+      AffiliationFetchThrottler::kGracePeriodAfterReconnectMs;
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(
+      true, kGraceMs * (1 - kPolicy.jitter_factor), kGraceMs));
+  throttler->InformOfNetworkRequestComplete(true);
+}
+
+TEST_F(AffiliationFetchThrottlerTest,
+       ConnectivityLostAndRestoredDuringRequest2) {
+  scoped_ptr<AffiliationFetchThrottler> throttler(CreateThrottler());
+
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+
+  SimulateHasNetworkConnectivity(false);
+  AssertNoReleaseUntilNoTasksRemain();
+  SimulateHasNetworkConnectivity(true);
+
+  const int64_t& kGraceMs =
+      AffiliationFetchThrottler::kGracePeriodAfterReconnectMs;
+  AssertNoReleaseForSecs(kGraceMs / base::Time::kMillisecondsPerSecond);
+  throttler->InformOfNetworkRequestComplete(true);
+
+  // The next request should not be held back.
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+}
+
+TEST_F(AffiliationFetchThrottlerTest, InstanceDestroyedWhileInBackoff) {
+  scoped_ptr<AffiliationFetchThrottler> throttler(CreateThrottler());
+
+  throttler->SignalNetworkRequestNeeded();
+  ASSERT_NO_FATAL_FAILURE(AssertReleaseInBetween(true, 0, 0));
+  throttler->InformOfNetworkRequestComplete(false);
+
+  throttler->SignalNetworkRequestNeeded();
+  throttler.reset();
+  EXPECT_EQ(1u, GetPendingTaskCount());
+  AssertNoReleaseUntilNoTasksRemain();
+}
+
+}  // namespace password_manager