content/browser/dom_storage/dom_storage_area_unittest.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/bind.h"
   6 #include "base/files/file_util.h"
   7 #include "base/files/scoped_temp_dir.h"
   8 #include "base/location.h"
   9 #include "base/message_loop/message_loop.h"
  10 #include "base/single_thread_task_runner.h"
  11 #include "base/strings/utf_string_conversions.h"
  12 #include "base/thread_task_runner_handle.h"
  13 #include "base/threading/sequenced_worker_pool.h"
  14 #include "base/time/time.h"
  15 #include "content/browser/dom_storage/dom_storage_area.h"
  16 #include "content/browser/dom_storage/dom_storage_database.h"
  17 #include "content/browser/dom_storage/dom_storage_database_adapter.h"
  18 #include "content/browser/dom_storage/dom_storage_task_runner.h"
  19 #include "content/browser/dom_storage/local_storage_database_adapter.h"
  20 #include "content/common/dom_storage/dom_storage_types.h"
  21 #include "content/public/browser/browser_thread.h"
  22 #include "testing/gtest/include/gtest/gtest.h"
  23
  24 using base::ASCIIToUTF16;
  25
  26 namespace content {
  27
  28 class DOMStorageAreaTest : public testing::Test {
  29  public:
  30   DOMStorageAreaTest()
  31     : kOrigin(GURL("http://dom_storage/")),
  32       kKey(ASCIIToUTF16("key")),
  33       kValue(ASCIIToUTF16("value")),
  34       kKey2(ASCIIToUTF16("key2")),
  35       kValue2(ASCIIToUTF16("value2")) {
  36   }
  37
  38   const GURL kOrigin;
  39   const base::string16 kKey;
  40   const base::string16 kValue;
  41   const base::string16 kKey2;
  42   const base::string16 kValue2;
  43
  44   // Method used in the CommitTasks test case.
  45   void InjectedCommitSequencingTask1(
  46       const scoped_refptr<DOMStorageArea>& area) {
  47     // At this point the StartCommitTimer task has run and
  48     // the OnCommitTimer task is queued. We want to inject after
  49     // that.
  50     base::ThreadTaskRunnerHandle::Get()->PostTask(
  51         FROM_HERE,
  52         base::Bind(&DOMStorageAreaTest::InjectedCommitSequencingTask2,
  53                    base::Unretained(this), area));
  54   }
  55
  56   void InjectedCommitSequencingTask2(
  57       const scoped_refptr<DOMStorageArea>& area) {
  58     // At this point the OnCommitTimer has run.
  59     // Verify that it put a commit in flight.
  60     EXPECT_EQ(1, area->commit_batches_in_flight_);
  61     EXPECT_FALSE(area->commit_batch_.get());
  62     EXPECT_TRUE(area->HasUncommittedChanges());
  63     // Make additional change and verify that a new commit batch
  64     // is created for that change.
  65     base::NullableString16 old_value;
  66     EXPECT_TRUE(area->SetItem(kKey2, kValue2, &old_value));
  67     EXPECT_TRUE(area->commit_batch_.get());
  68     EXPECT_EQ(1, area->commit_batches_in_flight_);
  69     EXPECT_TRUE(area->HasUncommittedChanges());
  70   }
  71
  72   // Class used in the CommitChangesAtShutdown test case.
  73   class VerifyChangesCommittedDatabase : public DOMStorageDatabase {
  74    public:
  75     VerifyChangesCommittedDatabase() {}
  76     ~VerifyChangesCommittedDatabase() override {
  77       const base::string16 kKey(ASCIIToUTF16("key"));
  78       const base::string16 kValue(ASCIIToUTF16("value"));
  79       DOMStorageValuesMap values;
  80       ReadAllValues(&values);
  81       EXPECT_EQ(1u, values.size());
  82       EXPECT_EQ(kValue, values[kKey].string());
  83     }
  84   };
  85
  86  private:
  87   base::MessageLoop message_loop_;
  88 };
  89
  90 TEST_F(DOMStorageAreaTest, DOMStorageAreaBasics) {
  91   scoped_refptr<DOMStorageArea> area(
  92       new DOMStorageArea(1, std::string(), kOrigin, NULL, NULL));
  93   base::string16 old_value;
  94   base::NullableString16 old_nullable_value;
  95   scoped_refptr<DOMStorageArea> copy;
  96
  97   // We don't focus on the underlying DOMStorageMap functionality
  98   // since that's covered by seperate unit tests.
  99   EXPECT_EQ(kOrigin, area->origin());
 100   EXPECT_EQ(1, area->namespace_id());
 101   EXPECT_EQ(0u, area->Length());
 102   EXPECT_TRUE(area->SetItem(kKey, kValue, &old_nullable_value));
 103   EXPECT_TRUE(area->SetItem(kKey2, kValue2, &old_nullable_value));
 104   EXPECT_FALSE(area->HasUncommittedChanges());
 105
 106   // Verify that a copy shares the same map.
 107   copy = area->ShallowCopy(2, std::string());
 108   EXPECT_EQ(kOrigin, copy->origin());
 109   EXPECT_EQ(2, copy->namespace_id());
 110   EXPECT_EQ(area->Length(), copy->Length());
 111   EXPECT_EQ(area->GetItem(kKey).string(), copy->GetItem(kKey).string());
 112   EXPECT_EQ(area->Key(0).string(), copy->Key(0).string());
 113   EXPECT_EQ(copy->map_.get(), area->map_.get());
 114
 115   // But will deep copy-on-write as needed.
 116   EXPECT_TRUE(area->RemoveItem(kKey, &old_value));
 117   EXPECT_NE(copy->map_.get(), area->map_.get());
 118   copy = area->ShallowCopy(2, std::string());
 119   EXPECT_EQ(copy->map_.get(), area->map_.get());
 120   EXPECT_TRUE(area->SetItem(kKey, kValue, &old_nullable_value));
 121   EXPECT_NE(copy->map_.get(), area->map_.get());
 122   copy = area->ShallowCopy(2, std::string());
 123   EXPECT_EQ(copy->map_.get(), area->map_.get());
 124   EXPECT_NE(0u, area->Length());
 125   EXPECT_TRUE(area->Clear());
 126   EXPECT_EQ(0u, area->Length());
 127   EXPECT_NE(copy->map_.get(), area->map_.get());
 128
 129   // Verify that once Shutdown(), behaves that way.
 130   area->Shutdown();
 131   EXPECT_TRUE(area->is_shutdown_);
 132   EXPECT_FALSE(area->map_.get());
 133   EXPECT_EQ(0u, area->Length());
 134   EXPECT_TRUE(area->Key(0).is_null());
 135   EXPECT_TRUE(area->GetItem(kKey).is_null());
 136   EXPECT_FALSE(area->SetItem(kKey, kValue, &old_nullable_value));
 137   EXPECT_FALSE(area->RemoveItem(kKey, &old_value));
 138   EXPECT_FALSE(area->Clear());
 139 }
 140
 141 TEST_F(DOMStorageAreaTest, BackingDatabaseOpened) {
 142   const int64 kSessionStorageNamespaceId = kLocalStorageNamespaceId + 1;
 143   base::ScopedTempDir temp_dir;
 144   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
 145   const base::FilePath kExpectedOriginFilePath = temp_dir.path().Append(
 146       DOMStorageArea::DatabaseFileNameFromOrigin(kOrigin));
 147
 148   // No directory, backing should be null.
 149   {
 150     scoped_refptr<DOMStorageArea> area(
 151         new DOMStorageArea(kOrigin, base::FilePath(), NULL));
 152     EXPECT_EQ(NULL, area->backing_.get());
 153     EXPECT_TRUE(area->is_initial_import_done_);
 154     EXPECT_FALSE(base::PathExists(kExpectedOriginFilePath));
 155   }
 156
 157   // Valid directory and origin but no session storage backing. Backing should
 158   // be null.
 159   {
 160     scoped_refptr<DOMStorageArea> area(
 161         new DOMStorageArea(kSessionStorageNamespaceId, std::string(), kOrigin,
 162                            NULL, NULL));
 163     EXPECT_EQ(NULL, area->backing_.get());
 164     EXPECT_TRUE(area->is_initial_import_done_);
 165
 166     base::NullableString16 old_value;
 167     EXPECT_TRUE(area->SetItem(kKey, kValue, &old_value));
 168     ASSERT_TRUE(old_value.is_null());
 169
 170     // Check that saving a value has still left us without a backing database.
 171     EXPECT_EQ(NULL, area->backing_.get());
 172     EXPECT_FALSE(base::PathExists(kExpectedOriginFilePath));
 173   }
 174
 175   // This should set up a DOMStorageArea that is correctly backed to disk.
 176   {
 177     scoped_refptr<DOMStorageArea> area(
 178         new DOMStorageArea(kOrigin, temp_dir.path(),
 179                            new MockDOMStorageTaskRunner(
 180                                base::ThreadTaskRunnerHandle::Get().get())));
 181
 182     EXPECT_TRUE(area->backing_.get());
 183     DOMStorageDatabase* database = static_cast<LocalStorageDatabaseAdapter*>(
 184         area->backing_.get())->db_.get();
 185     EXPECT_FALSE(database->IsOpen());
 186     EXPECT_FALSE(area->is_initial_import_done_);
 187
 188     // Inject an in-memory db to speed up the test.
 189     // We will verify that something is written into the database but not
 190     // that a file is written to disk - DOMStorageDatabase unit tests cover
 191     // that.
 192     area->backing_.reset(new LocalStorageDatabaseAdapter());
 193
 194     // Need to write something to ensure that the database is created.
 195     base::NullableString16 old_value;
 196     EXPECT_TRUE(area->SetItem(kKey, kValue, &old_value));
 197     ASSERT_TRUE(old_value.is_null());
 198     EXPECT_TRUE(area->is_initial_import_done_);
 199     EXPECT_TRUE(area->commit_batch_.get());
 200     EXPECT_EQ(0, area->commit_batches_in_flight_);
 201
 202     base::MessageLoop::current()->RunUntilIdle();
 203
 204     EXPECT_FALSE(area->commit_batch_.get());
 205     EXPECT_EQ(0, area->commit_batches_in_flight_);
 206     database = static_cast<LocalStorageDatabaseAdapter*>(
 207         area->backing_.get())->db_.get();
 208     EXPECT_TRUE(database->IsOpen());
 209     EXPECT_EQ(1u, area->Length());
 210     EXPECT_EQ(kValue, area->GetItem(kKey).string());
 211
 212     // Verify the content made it to the in memory database.
 213     DOMStorageValuesMap values;
 214     area->backing_->ReadAllValues(&values);
 215     EXPECT_EQ(1u, values.size());
 216     EXPECT_EQ(kValue, values[kKey].string());
 217   }
 218 }
 219
 220 TEST_F(DOMStorageAreaTest, CommitTasks) {
 221   base::ScopedTempDir temp_dir;
 222   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
 223
 224   scoped_refptr<DOMStorageArea> area(new DOMStorageArea(
 225       kOrigin, temp_dir.path(),
 226       new MockDOMStorageTaskRunner(base::ThreadTaskRunnerHandle::Get().get())));
 227   // Inject an in-memory db to speed up the test.
 228   area->backing_.reset(new LocalStorageDatabaseAdapter());
 229
 230   // Unrelated to commits, but while we're here, see that querying Length()
 231   // causes the backing database to be opened and presumably read from.
 232   EXPECT_FALSE(area->is_initial_import_done_);
 233   EXPECT_EQ(0u, area->Length());
 234   EXPECT_TRUE(area->is_initial_import_done_);
 235
 236   DOMStorageValuesMap values;
 237   base::NullableString16 old_value;
 238
 239   // See that changes are batched up.
 240   EXPECT_FALSE(area->commit_batch_.get());
 241   EXPECT_TRUE(area->SetItem(kKey, kValue, &old_value));
 242   EXPECT_TRUE(area->HasUncommittedChanges());
 243   EXPECT_TRUE(area->commit_batch_.get());
 244   EXPECT_FALSE(area->commit_batch_->clear_all_first);
 245   EXPECT_EQ(1u, area->commit_batch_->changed_values.size());
 246   EXPECT_TRUE(area->SetItem(kKey2, kValue2, &old_value));
 247   EXPECT_TRUE(area->commit_batch_.get());
 248   EXPECT_FALSE(area->commit_batch_->clear_all_first);
 249   EXPECT_EQ(2u, area->commit_batch_->changed_values.size());
 250   base::MessageLoop::current()->RunUntilIdle();
 251   EXPECT_FALSE(area->HasUncommittedChanges());
 252   EXPECT_FALSE(area->commit_batch_.get());
 253   EXPECT_EQ(0, area->commit_batches_in_flight_);
 254   // Verify the changes made it to the database.
 255   values.clear();
 256   area->backing_->ReadAllValues(&values);
 257   EXPECT_EQ(2u, values.size());
 258   EXPECT_EQ(kValue, values[kKey].string());
 259   EXPECT_EQ(kValue2, values[kKey2].string());
 260
 261   // See that clear is handled properly.
 262   EXPECT_TRUE(area->Clear());
 263   EXPECT_TRUE(area->commit_batch_.get());
 264   EXPECT_TRUE(area->commit_batch_->clear_all_first);
 265   EXPECT_TRUE(area->commit_batch_->changed_values.empty());
 266   base::MessageLoop::current()->RunUntilIdle();
 267   EXPECT_FALSE(area->commit_batch_.get());
 268   EXPECT_EQ(0, area->commit_batches_in_flight_);
 269   // Verify the changes made it to the database.
 270   values.clear();
 271   area->backing_->ReadAllValues(&values);
 272   EXPECT_TRUE(values.empty());
 273
 274   // See that if changes accrue while a commit is "in flight"
 275   // those will also get committed.
 276   EXPECT_TRUE(area->SetItem(kKey, kValue, &old_value));
 277   EXPECT_TRUE(area->HasUncommittedChanges());
 278   // At this point the StartCommitTimer task has been posted to the after
 279   // startup task queue. We inject another task in the queue that will
 280   // execute when the CommitChanges task is inflight. From within our
 281   // injected task, we'll make an additional SetItem() call and verify
 282   // that a new commit batch is created for that additional change.
 283   BrowserThread::PostAfterStartupTask(
 284       FROM_HERE, base::ThreadTaskRunnerHandle::Get(),
 285       base::Bind(&DOMStorageAreaTest::InjectedCommitSequencingTask1,
 286                  base::Unretained(this),
 287                  area));
 288   base::MessageLoop::current()->RunUntilIdle();
 289   EXPECT_TRUE(area->HasOneRef());
 290   EXPECT_FALSE(area->HasUncommittedChanges());
 291   // Verify the changes made it to the database.
 292   values.clear();
 293   area->backing_->ReadAllValues(&values);
 294   EXPECT_EQ(2u, values.size());
 295   EXPECT_EQ(kValue, values[kKey].string());
 296   EXPECT_EQ(kValue2, values[kKey2].string());
 297 }
 298
 299 TEST_F(DOMStorageAreaTest, CommitChangesAtShutdown) {
 300   base::ScopedTempDir temp_dir;
 301   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
 302   scoped_refptr<DOMStorageArea> area(new DOMStorageArea(
 303       kOrigin, temp_dir.path(),
 304       new MockDOMStorageTaskRunner(base::ThreadTaskRunnerHandle::Get().get())));
 305
 306   // Inject an in-memory db to speed up the test and also to verify
 307   // the final changes are commited in it's dtor.
 308   static_cast<LocalStorageDatabaseAdapter*>(area->backing_.get())->db_.reset(
 309       new VerifyChangesCommittedDatabase());
 310
 311   DOMStorageValuesMap values;
 312   base::NullableString16 old_value;
 313   EXPECT_TRUE(area->SetItem(kKey, kValue, &old_value));
 314   EXPECT_TRUE(area->HasUncommittedChanges());
 315   area->backing_->ReadAllValues(&values);
 316   EXPECT_TRUE(values.empty());  // not committed yet
 317   area->Shutdown();
 318   base::MessageLoop::current()->RunUntilIdle();
 319   EXPECT_TRUE(area->HasOneRef());
 320   EXPECT_FALSE(area->backing_.get());
 321   // The VerifyChangesCommittedDatabase destructor verifies values
 322   // were committed.
 323 }
 324
 325 TEST_F(DOMStorageAreaTest, DeleteOrigin) {
 326   base::ScopedTempDir temp_dir;
 327   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
 328   scoped_refptr<DOMStorageArea> area(new DOMStorageArea(
 329       kOrigin, temp_dir.path(),
 330       new MockDOMStorageTaskRunner(base::ThreadTaskRunnerHandle::Get().get())));
 331
 332   // This test puts files on disk.
 333   base::FilePath db_file_path = static_cast<LocalStorageDatabaseAdapter*>(
 334       area->backing_.get())->db_->file_path();
 335   base::FilePath db_journal_file_path =
 336       DOMStorageDatabase::GetJournalFilePath(db_file_path);
 337
 338   // Nothing bad should happen when invoked w/o any files on disk.
 339   area->DeleteOrigin();
 340   EXPECT_FALSE(base::PathExists(db_file_path));
 341
 342   // Commit something in the database and then delete.
 343   base::NullableString16 old_value;
 344   area->SetItem(kKey, kValue, &old_value);
 345   base::MessageLoop::current()->RunUntilIdle();
 346   EXPECT_TRUE(base::PathExists(db_file_path));
 347   area->DeleteOrigin();
 348   EXPECT_EQ(0u, area->Length());
 349   EXPECT_FALSE(base::PathExists(db_file_path));
 350   EXPECT_FALSE(base::PathExists(db_journal_file_path));
 351
 352   // Put some uncommitted changes to a non-existing database in
 353   // and then delete. No file ever gets created in this case.
 354   area->SetItem(kKey, kValue, &old_value);
 355   EXPECT_TRUE(area->HasUncommittedChanges());
 356   EXPECT_EQ(1u, area->Length());
 357   area->DeleteOrigin();
 358   EXPECT_TRUE(area->HasUncommittedChanges());
 359   EXPECT_EQ(0u, area->Length());
 360   base::MessageLoop::current()->RunUntilIdle();
 361   EXPECT_FALSE(area->HasUncommittedChanges());
 362   EXPECT_FALSE(base::PathExists(db_file_path));
 363
 364   // Put some uncommitted changes to a an existing database in
 365   // and then delete.
 366   area->SetItem(kKey, kValue, &old_value);
 367   base::MessageLoop::current()->RunUntilIdle();
 368   EXPECT_TRUE(base::PathExists(db_file_path));
 369   area->SetItem(kKey2, kValue2, &old_value);
 370   EXPECT_TRUE(area->HasUncommittedChanges());
 371   EXPECT_EQ(2u, area->Length());
 372   area->DeleteOrigin();
 373   EXPECT_TRUE(area->HasUncommittedChanges());
 374   EXPECT_EQ(0u, area->Length());
 375   base::MessageLoop::current()->RunUntilIdle();
 376   EXPECT_FALSE(area->HasUncommittedChanges());
 377   // Since the area had uncommitted changes at the time delete
 378   // was called, the file will linger until the shutdown time.
 379   EXPECT_TRUE(base::PathExists(db_file_path));
 380   area->Shutdown();
 381   base::MessageLoop::current()->RunUntilIdle();
 382   EXPECT_FALSE(base::PathExists(db_file_path));
 383 }
 384
 385 TEST_F(DOMStorageAreaTest, PurgeMemory) {
 386   base::ScopedTempDir temp_dir;
 387   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
 388   scoped_refptr<DOMStorageArea> area(new DOMStorageArea(
 389       kOrigin, temp_dir.path(),
 390       new MockDOMStorageTaskRunner(base::ThreadTaskRunnerHandle::Get().get())));
 391
 392   // Inject an in-memory db to speed up the test.
 393   area->backing_.reset(new LocalStorageDatabaseAdapter());
 394
 395   // Unowned ptrs we use to verify that 'purge' has happened.
 396   DOMStorageDatabase* original_backing =
 397       static_cast<LocalStorageDatabaseAdapter*>(
 398           area->backing_.get())->db_.get();
 399   DOMStorageMap* original_map = area->map_.get();
 400
 401   // Should do no harm when called on a newly constructed object.
 402   EXPECT_FALSE(area->is_initial_import_done_);
 403   area->PurgeMemory();
 404   EXPECT_FALSE(area->is_initial_import_done_);
 405   DOMStorageDatabase* new_backing = static_cast<LocalStorageDatabaseAdapter*>(
 406       area->backing_.get())->db_.get();
 407   EXPECT_EQ(original_backing, new_backing);
 408   EXPECT_EQ(original_map, area->map_.get());
 409
 410   // Should not do anything when commits are pending.
 411   base::NullableString16 old_value;
 412   area->SetItem(kKey, kValue, &old_value);
 413   EXPECT_TRUE(area->is_initial_import_done_);
 414   EXPECT_TRUE(area->HasUncommittedChanges());
 415   area->PurgeMemory();
 416   EXPECT_TRUE(area->is_initial_import_done_);
 417   EXPECT_TRUE(area->HasUncommittedChanges());
 418   new_backing = static_cast<LocalStorageDatabaseAdapter*>(
 419       area->backing_.get())->db_.get();
 420   EXPECT_EQ(original_backing, new_backing);
 421   EXPECT_EQ(original_map, area->map_.get());
 422
 423   // Commit the changes from above,
 424   base::MessageLoop::current()->RunUntilIdle();
 425   EXPECT_FALSE(area->HasUncommittedChanges());
 426   new_backing = static_cast<LocalStorageDatabaseAdapter*>(
 427       area->backing_.get())->db_.get();
 428   EXPECT_EQ(original_backing, new_backing);
 429   EXPECT_EQ(original_map, area->map_.get());
 430
 431   // Should drop caches and reset database connections
 432   // when invoked on an area that's loaded up primed.
 433   area->PurgeMemory();
 434   EXPECT_FALSE(area->is_initial_import_done_);
 435   new_backing = static_cast<LocalStorageDatabaseAdapter*>(
 436       area->backing_.get())->db_.get();
 437   EXPECT_NE(original_backing, new_backing);
 438   EXPECT_NE(original_map, area->map_.get());
 439 }
 440
 441 TEST_F(DOMStorageAreaTest, DatabaseFileNames) {
 442   struct {
 443     const char* origin;
 444     const char* file_name;
 445     const char* journal_file_name;
 446   } kCases[] = {
 447     { "https://www.google.com/",
 448       "https_www.google.com_0.localstorage",
 449       "https_www.google.com_0.localstorage-journal" },
 450     { "http://www.google.com:8080/",
 451       "http_www.google.com_8080.localstorage",
 452       "http_www.google.com_8080.localstorage-journal" },
 453     { "file:///",
 454       "file__0.localstorage",
 455       "file__0.localstorage-journal" },
 456   };
 457
 458   for (size_t i = 0; i < arraysize(kCases); ++i) {
 459     GURL origin = GURL(kCases[i].origin).GetOrigin();
 460     base::FilePath file_name =
 461         base::FilePath().AppendASCII(kCases[i].file_name);
 462     base::FilePath journal_file_name =
 463         base::FilePath().AppendASCII(kCases[i].journal_file_name);
 464
 465     EXPECT_EQ(file_name,
 466               DOMStorageArea::DatabaseFileNameFromOrigin(origin));
 467     EXPECT_EQ(origin,
 468               DOMStorageArea::OriginFromDatabaseFileName(file_name));
 469     EXPECT_EQ(journal_file_name,
 470               DOMStorageDatabase::GetJournalFilePath(file_name));
 471   }
 472
 473   // Also test some DOMStorageDatabase::GetJournalFilePath cases here.
 474   base::FilePath parent = base::FilePath().AppendASCII("a").AppendASCII("b");
 475   EXPECT_EQ(
 476       parent.AppendASCII("file-journal"),
 477       DOMStorageDatabase::GetJournalFilePath(parent.AppendASCII("file")));
 478   EXPECT_EQ(
 479       base::FilePath().AppendASCII("-journal"),
 480       DOMStorageDatabase::GetJournalFilePath(base::FilePath()));
 481   EXPECT_EQ(
 482       base::FilePath().AppendASCII(".extensiononly-journal"),
 483       DOMStorageDatabase::GetJournalFilePath(
 484           base::FilePath().AppendASCII(".extensiononly")));
 485 }
 486
 487 TEST_F(DOMStorageAreaTest, RateLimiter) {
 488   // Limit to 1000 samples per second
 489   DOMStorageArea::RateLimiter rate_limiter(
 490       1000, base::TimeDelta::FromSeconds(1));
 491
 492   // No samples have been added so no time/delay should be needed.
 493   EXPECT_EQ(base::TimeDelta(),
 494             rate_limiter.ComputeTimeNeeded());
 495   EXPECT_EQ(base::TimeDelta(),
 496             rate_limiter.ComputeDelayNeeded(base::TimeDelta()));
 497   EXPECT_EQ(base::TimeDelta(),
 498             rate_limiter.ComputeDelayNeeded(base::TimeDelta::FromDays(1)));
 499
 500   // Add a seconds worth of samples.
 501   rate_limiter.add_samples(1000);
 502   EXPECT_EQ(base::TimeDelta::FromSeconds(1),
 503             rate_limiter.ComputeTimeNeeded());
 504   EXPECT_EQ(base::TimeDelta::FromSeconds(1),
 505             rate_limiter.ComputeDelayNeeded(base::TimeDelta()));
 506   EXPECT_EQ(base::TimeDelta(),
 507             rate_limiter.ComputeDelayNeeded(base::TimeDelta::FromSeconds(1)));
 508   EXPECT_EQ(base::TimeDelta::FromMilliseconds(250),
 509             rate_limiter.ComputeDelayNeeded(
 510                 base::TimeDelta::FromMilliseconds(750)));
 511   EXPECT_EQ(base::TimeDelta(),
 512             rate_limiter.ComputeDelayNeeded(
 513                 base::TimeDelta::FromDays(1)));
 514
 515   // And another half seconds worth.
 516   rate_limiter.add_samples(500);
 517   EXPECT_EQ(base::TimeDelta::FromMilliseconds(1500),
 518             rate_limiter.ComputeTimeNeeded());
 519   EXPECT_EQ(base::TimeDelta::FromMilliseconds(1500),
 520             rate_limiter.ComputeDelayNeeded(base::TimeDelta()));
 521   EXPECT_EQ(base::TimeDelta::FromMilliseconds(500),
 522             rate_limiter.ComputeDelayNeeded(base::TimeDelta::FromSeconds(1)));
 523   EXPECT_EQ(base::TimeDelta::FromMilliseconds(750),
 524             rate_limiter.ComputeDelayNeeded(
 525                 base::TimeDelta::FromMilliseconds(750)));
 526   EXPECT_EQ(base::TimeDelta(),
 527             rate_limiter.ComputeDelayNeeded(
 528                 base::TimeDelta::FromMilliseconds(1500)));
 529   EXPECT_EQ(base::TimeDelta(),
 530             rate_limiter.ComputeDelayNeeded(
 531                 base::TimeDelta::FromDays(1)));
 532 }
 533
 534 }  // namespace content