base/metrics/field_trial_unittest.cc

   1 // Copyright (c) 2012 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/metrics/field_trial.h"
   6
   7 #include "base/build_time.h"
   8 #include "base/message_loop/message_loop.h"
   9 #include "base/rand_util.h"
  10 #include "base/run_loop.h"
  11 #include "base/strings/string_number_conversions.h"
  12 #include "base/strings/stringprintf.h"
  13 #include "testing/gtest/include/gtest/gtest.h"
  14
  15 namespace base {
  16
  17 namespace {
  18
  19 // Default group name used by several tests.
  20 const char kDefaultGroupName[] = "DefaultGroup";
  21
  22 // Call FieldTrialList::FactoryGetFieldTrial() with a future expiry date.
  23 scoped_refptr<base::FieldTrial> CreateFieldTrial(
  24     const std::string& trial_name,
  25     int total_probability,
  26     const std::string& default_group_name,
  27     int* default_group_number) {
  28   return FieldTrialList::FactoryGetFieldTrial(
  29       trial_name, total_probability, default_group_name,
  30       base::FieldTrialList::kNoExpirationYear, 1, 1,
  31       base::FieldTrial::SESSION_RANDOMIZED, default_group_number);
  32 }
  33
  34 int OneYearBeforeBuildTime() {
  35   Time one_year_before_build_time = GetBuildTime() - TimeDelta::FromDays(365);
  36   Time::Exploded exploded;
  37   one_year_before_build_time.LocalExplode(&exploded);
  38   return exploded.year;
  39 }
  40
  41 // FieldTrialList::Observer implementation for testing.
  42 class TestFieldTrialObserver : public FieldTrialList::Observer {
  43  public:
  44   TestFieldTrialObserver() {
  45     FieldTrialList::AddObserver(this);
  46   }
  47
  48   ~TestFieldTrialObserver() override { FieldTrialList::RemoveObserver(this); }
  49
  50   void OnFieldTrialGroupFinalized(const std::string& trial,
  51                                   const std::string& group) override {
  52     trial_name_ = trial;
  53     group_name_ = group;
  54   }
  55
  56   const std::string& trial_name() const { return trial_name_; }
  57   const std::string& group_name() const { return group_name_; }
  58
  59  private:
  60   std::string trial_name_;
  61   std::string group_name_;
  62
  63   DISALLOW_COPY_AND_ASSIGN(TestFieldTrialObserver);
  64 };
  65
  66 }  // namespace
  67
  68 class FieldTrialTest : public testing::Test {
  69  public:
  70   FieldTrialTest() : trial_list_(NULL) {}
  71
  72  private:
  73   MessageLoop message_loop_;
  74   FieldTrialList trial_list_;
  75 };
  76
  77 // Test registration, and also check that destructors are called for trials
  78 // (and that Valgrind doesn't catch us leaking).
  79 TEST_F(FieldTrialTest, Registration) {
  80   const char name1[] = "name 1 test";
  81   const char name2[] = "name 2 test";
  82   EXPECT_FALSE(FieldTrialList::Find(name1));
  83   EXPECT_FALSE(FieldTrialList::Find(name2));
  84
  85   scoped_refptr<FieldTrial> trial1 =
  86       CreateFieldTrial(name1, 10, "default name 1 test", NULL);
  87   EXPECT_EQ(FieldTrial::kNotFinalized, trial1->group_);
  88   EXPECT_EQ(name1, trial1->trial_name());
  89   EXPECT_EQ("", trial1->group_name_internal());
  90
  91   trial1->AppendGroup(std::string(), 7);
  92
  93   EXPECT_EQ(trial1.get(), FieldTrialList::Find(name1));
  94   EXPECT_FALSE(FieldTrialList::Find(name2));
  95
  96   scoped_refptr<FieldTrial> trial2 =
  97       CreateFieldTrial(name2, 10, "default name 2 test", NULL);
  98   EXPECT_EQ(FieldTrial::kNotFinalized, trial2->group_);
  99   EXPECT_EQ(name2, trial2->trial_name());
 100   EXPECT_EQ("", trial2->group_name_internal());
 101
 102   trial2->AppendGroup("a first group", 7);
 103
 104   EXPECT_EQ(trial1.get(), FieldTrialList::Find(name1));
 105   EXPECT_EQ(trial2.get(), FieldTrialList::Find(name2));
 106   // Note: FieldTrialList should delete the objects at shutdown.
 107 }
 108
 109 TEST_F(FieldTrialTest, AbsoluteProbabilities) {
 110   char always_true[] = " always true";
 111   char default_always_true[] = " default always true";
 112   char always_false[] = " always false";
 113   char default_always_false[] = " default always false";
 114   for (int i = 1; i < 250; ++i) {
 115     // Try lots of names, by changing the first character of the name.
 116     char c = static_cast<char>(i);
 117     always_true[0] = c;
 118     default_always_true[0] = c;
 119     always_false[0] = c;
 120     default_always_false[0] = c;
 121
 122     scoped_refptr<FieldTrial> trial_true =
 123         CreateFieldTrial(always_true, 10, default_always_true, NULL);
 124     const std::string winner = "TheWinner";
 125     int winner_group = trial_true->AppendGroup(winner, 10);
 126
 127     EXPECT_EQ(winner_group, trial_true->group());
 128     EXPECT_EQ(winner, trial_true->group_name());
 129
 130     scoped_refptr<FieldTrial> trial_false =
 131         CreateFieldTrial(always_false, 10, default_always_false, NULL);
 132     int loser_group = trial_false->AppendGroup("ALoser", 0);
 133
 134     EXPECT_NE(loser_group, trial_false->group());
 135   }
 136 }
 137
 138 TEST_F(FieldTrialTest, RemainingProbability) {
 139   // First create a test that hasn't had a winner yet.
 140   const std::string winner = "Winner";
 141   const std::string loser = "Loser";
 142   scoped_refptr<FieldTrial> trial;
 143   int counter = 0;
 144   int default_group_number = -1;
 145   do {
 146     std::string name = StringPrintf("trial%d", ++counter);
 147     trial = CreateFieldTrial(name, 10, winner, &default_group_number);
 148     trial->AppendGroup(loser, 5);  // 50% chance of not being chosen.
 149     // If a group is not assigned, group_ will be kNotFinalized.
 150   } while (trial->group_ != FieldTrial::kNotFinalized);
 151
 152   // And that 'default' group (winner) should always win.
 153   EXPECT_EQ(default_group_number, trial->group());
 154
 155   // And that winner should ALWAYS win.
 156   EXPECT_EQ(winner, trial->group_name());
 157 }
 158
 159 TEST_F(FieldTrialTest, FiftyFiftyProbability) {
 160   // Check that even with small divisors, we have the proper probabilities, and
 161   // all outcomes are possible.  Since this is a 50-50 test, it should get both
 162   // outcomes in a few tries, but we'll try no more than 100 times (and be flaky
 163   // with probability around 1 in 2^99).
 164   bool first_winner = false;
 165   bool second_winner = false;
 166   int counter = 0;
 167   do {
 168     std::string name = base::StringPrintf("FiftyFifty%d", ++counter);
 169     std::string default_group_name = base::StringPrintf("Default FiftyFifty%d",
 170                                                         ++counter);
 171     scoped_refptr<FieldTrial> trial =
 172         CreateFieldTrial(name, 2, default_group_name, NULL);
 173     trial->AppendGroup("first", 1);  // 50% chance of being chosen.
 174     // If group_ is kNotFinalized, then a group assignement hasn't been done.
 175     if (trial->group_ != FieldTrial::kNotFinalized) {
 176       first_winner = true;
 177       continue;
 178     }
 179     trial->AppendGroup("second", 1);  // Always chosen at this point.
 180     EXPECT_NE(FieldTrial::kNotFinalized, trial->group());
 181     second_winner = true;
 182   } while ((!second_winner || !first_winner) && counter < 100);
 183   EXPECT_TRUE(second_winner);
 184   EXPECT_TRUE(first_winner);
 185 }
 186
 187 TEST_F(FieldTrialTest, MiddleProbabilities) {
 188   char name[] = " same name";
 189   char default_group_name[] = " default same name";
 190   bool false_event_seen = false;
 191   bool true_event_seen = false;
 192   for (int i = 1; i < 250; ++i) {
 193     char c = static_cast<char>(i);
 194     name[0] = c;
 195     default_group_name[0] = c;
 196     scoped_refptr<FieldTrial> trial =
 197         CreateFieldTrial(name, 10, default_group_name, NULL);
 198     int might_win = trial->AppendGroup("MightWin", 5);
 199
 200     if (trial->group() == might_win) {
 201       true_event_seen = true;
 202     } else {
 203       false_event_seen = true;
 204     }
 205     if (false_event_seen && true_event_seen)
 206       return;  // Successful test!!!
 207   }
 208   // Very surprising to get here. Probability should be around 1 in 2 ** 250.
 209   // One of the following will fail.
 210   EXPECT_TRUE(false_event_seen);
 211   EXPECT_TRUE(true_event_seen);
 212 }
 213
 214 TEST_F(FieldTrialTest, OneWinner) {
 215   char name[] = "Some name";
 216   char default_group_name[] = "Default some name";
 217   int group_count(10);
 218
 219   int default_group_number = -1;
 220   scoped_refptr<FieldTrial> trial =
 221       CreateFieldTrial(name, group_count, default_group_name, NULL);
 222   int winner_index(-2);
 223   std::string winner_name;
 224
 225   for (int i = 1; i <= group_count; ++i) {
 226     int might_win = trial->AppendGroup(std::string(), 1);
 227
 228     // Because we keep appending groups, we want to see if the last group that
 229     // was added has been assigned or not.
 230     if (trial->group_ == might_win) {
 231       EXPECT_EQ(-2, winner_index);
 232       winner_index = might_win;
 233       StringAppendF(&winner_name, "%d", might_win);
 234       EXPECT_EQ(winner_name, trial->group_name());
 235     }
 236   }
 237   EXPECT_GE(winner_index, 0);
 238   // Since all groups cover the total probability, we should not have
 239   // chosen the default group.
 240   EXPECT_NE(trial->group(), default_group_number);
 241   EXPECT_EQ(trial->group(), winner_index);
 242   EXPECT_EQ(trial->group_name(), winner_name);
 243 }
 244
 245 TEST_F(FieldTrialTest, DisableProbability) {
 246   const std::string default_group_name = "Default group";
 247   const std::string loser = "Loser";
 248   const std::string name = "Trial";
 249
 250   // Create a field trail that has expired.
 251   int default_group_number = -1;
 252   FieldTrial* trial = FieldTrialList::FactoryGetFieldTrial(
 253       name, 1000000000, default_group_name, OneYearBeforeBuildTime(), 1, 1,
 254       FieldTrial::SESSION_RANDOMIZED,
 255       &default_group_number);
 256   trial->AppendGroup(loser, 999999999);  // 99.9999999% chance of being chosen.
 257
 258   // Because trial has expired, we should always be in the default group.
 259   EXPECT_EQ(default_group_number, trial->group());
 260
 261   // And that default_group_name should ALWAYS win.
 262   EXPECT_EQ(default_group_name, trial->group_name());
 263 }
 264
 265 TEST_F(FieldTrialTest, ActiveGroups) {
 266   std::string no_group("No Group");
 267   scoped_refptr<FieldTrial> trial =
 268       CreateFieldTrial(no_group, 10, "Default", NULL);
 269
 270   // There is no winner yet, so no NameGroupId should be returned.
 271   FieldTrial::ActiveGroup active_group;
 272   EXPECT_FALSE(trial->GetActiveGroup(&active_group));
 273
 274   // Create a single winning group.
 275   std::string one_winner("One Winner");
 276   trial = CreateFieldTrial(one_winner, 10, "Default", NULL);
 277   std::string winner("Winner");
 278   trial->AppendGroup(winner, 10);
 279   EXPECT_FALSE(trial->GetActiveGroup(&active_group));
 280   // Finalize the group selection by accessing the selected group.
 281   trial->group();
 282   EXPECT_TRUE(trial->GetActiveGroup(&active_group));
 283   EXPECT_EQ(one_winner, active_group.trial_name);
 284   EXPECT_EQ(winner, active_group.group_name);
 285
 286   std::string multi_group("MultiGroup");
 287   scoped_refptr<FieldTrial> multi_group_trial =
 288       CreateFieldTrial(multi_group, 9, "Default", NULL);
 289
 290   multi_group_trial->AppendGroup("Me", 3);
 291   multi_group_trial->AppendGroup("You", 3);
 292   multi_group_trial->AppendGroup("Them", 3);
 293   EXPECT_FALSE(multi_group_trial->GetActiveGroup(&active_group));
 294   // Finalize the group selection by accessing the selected group.
 295   multi_group_trial->group();
 296   EXPECT_TRUE(multi_group_trial->GetActiveGroup(&active_group));
 297   EXPECT_EQ(multi_group, active_group.trial_name);
 298   EXPECT_EQ(multi_group_trial->group_name(), active_group.group_name);
 299
 300   // Now check if the list is built properly...
 301   FieldTrial::ActiveGroups active_groups;
 302   FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
 303   EXPECT_EQ(2U, active_groups.size());
 304   for (size_t i = 0; i < active_groups.size(); ++i) {
 305     // Order is not guaranteed, so check all values.
 306     EXPECT_NE(no_group, active_groups[i].trial_name);
 307     EXPECT_TRUE(one_winner != active_groups[i].trial_name ||
 308                 winner == active_groups[i].group_name);
 309     EXPECT_TRUE(multi_group != active_groups[i].trial_name ||
 310                 multi_group_trial->group_name() == active_groups[i].group_name);
 311   }
 312 }
 313
 314 TEST_F(FieldTrialTest, AllGroups) {
 315   FieldTrial::FieldTrialState field_trial_state;
 316   std::string one_winner("One Winner");
 317   scoped_refptr<FieldTrial> trial =
 318       CreateFieldTrial(one_winner, 10, "Default", NULL);
 319   std::string winner("Winner");
 320   trial->AppendGroup(winner, 10);
 321   EXPECT_TRUE(trial->GetState(&field_trial_state));
 322   EXPECT_EQ(one_winner, field_trial_state.trial_name);
 323   EXPECT_EQ(winner, field_trial_state.group_name);
 324   trial->group();
 325   EXPECT_TRUE(trial->GetState(&field_trial_state));
 326   EXPECT_EQ(one_winner, field_trial_state.trial_name);
 327   EXPECT_EQ(winner, field_trial_state.group_name);
 328
 329   std::string multi_group("MultiGroup");
 330   scoped_refptr<FieldTrial> multi_group_trial =
 331       CreateFieldTrial(multi_group, 9, "Default", NULL);
 332
 333   multi_group_trial->AppendGroup("Me", 3);
 334   multi_group_trial->AppendGroup("You", 3);
 335   multi_group_trial->AppendGroup("Them", 3);
 336   EXPECT_TRUE(multi_group_trial->GetState(&field_trial_state));
 337   // Finalize the group selection by accessing the selected group.
 338   multi_group_trial->group();
 339   EXPECT_TRUE(multi_group_trial->GetState(&field_trial_state));
 340   EXPECT_EQ(multi_group, field_trial_state.trial_name);
 341   EXPECT_EQ(multi_group_trial->group_name(), field_trial_state.group_name);
 342 }
 343
 344 TEST_F(FieldTrialTest, ActiveGroupsNotFinalized) {
 345   const char kTrialName[] = "TestTrial";
 346   const char kSecondaryGroupName[] = "SecondaryGroup";
 347
 348   int default_group = -1;
 349   scoped_refptr<FieldTrial> trial =
 350       CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
 351   const int secondary_group = trial->AppendGroup(kSecondaryGroupName, 50);
 352
 353   // Before |group()| is called, |GetActiveGroup()| should return false.
 354   FieldTrial::ActiveGroup active_group;
 355   EXPECT_FALSE(trial->GetActiveGroup(&active_group));
 356
 357   // |GetActiveFieldTrialGroups()| should also not include the trial.
 358   FieldTrial::ActiveGroups active_groups;
 359   FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
 360   EXPECT_TRUE(active_groups.empty());
 361
 362   // After |group()| has been called, both APIs should succeed.
 363   const int chosen_group = trial->group();
 364   EXPECT_TRUE(chosen_group == default_group || chosen_group == secondary_group);
 365
 366   EXPECT_TRUE(trial->GetActiveGroup(&active_group));
 367   EXPECT_EQ(kTrialName, active_group.trial_name);
 368   if (chosen_group == default_group)
 369     EXPECT_EQ(kDefaultGroupName, active_group.group_name);
 370   else
 371     EXPECT_EQ(kSecondaryGroupName, active_group.group_name);
 372
 373   FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
 374   ASSERT_EQ(1U, active_groups.size());
 375   EXPECT_EQ(kTrialName, active_groups[0].trial_name);
 376   EXPECT_EQ(active_group.group_name, active_groups[0].group_name);
 377 }
 378
 379 TEST_F(FieldTrialTest, Save) {
 380   std::string save_string;
 381
 382   scoped_refptr<FieldTrial> trial =
 383       CreateFieldTrial("Some name", 10, "Default some name", NULL);
 384   // There is no winner yet, so no textual group name is associated with trial.
 385   // In this case, the trial should not be included.
 386   EXPECT_EQ("", trial->group_name_internal());
 387   FieldTrialList::StatesToString(&save_string);
 388   EXPECT_EQ("", save_string);
 389   save_string.clear();
 390
 391   // Create a winning group.
 392   trial->AppendGroup("Winner", 10);
 393   // Finalize the group selection by accessing the selected group.
 394   trial->group();
 395   FieldTrialList::StatesToString(&save_string);
 396   EXPECT_EQ("Some name/Winner/", save_string);
 397   save_string.clear();
 398
 399   // Create a second trial and winning group.
 400   scoped_refptr<FieldTrial> trial2 =
 401       CreateFieldTrial("xxx", 10, "Default xxx", NULL);
 402   trial2->AppendGroup("yyyy", 10);
 403   // Finalize the group selection by accessing the selected group.
 404   trial2->group();
 405
 406   FieldTrialList::StatesToString(&save_string);
 407   // We assume names are alphabetized... though this is not critical.
 408   EXPECT_EQ("Some name/Winner/xxx/yyyy/", save_string);
 409   save_string.clear();
 410
 411   // Create a third trial with only the default group.
 412   scoped_refptr<FieldTrial> trial3 =
 413       CreateFieldTrial("zzz", 10, "default", NULL);
 414   // Finalize the group selection by accessing the selected group.
 415   trial3->group();
 416
 417   FieldTrialList::StatesToString(&save_string);
 418   EXPECT_EQ("Some name/Winner/xxx/yyyy/zzz/default/", save_string);
 419 }
 420
 421 TEST_F(FieldTrialTest, SaveAll) {
 422   std::string save_string;
 423
 424   scoped_refptr<FieldTrial> trial =
 425       CreateFieldTrial("Some name", 10, "Default some name", NULL);
 426   EXPECT_EQ("", trial->group_name_internal());
 427   FieldTrialList::AllStatesToString(&save_string);
 428   EXPECT_EQ("Some name/Default some name/", save_string);
 429   save_string.clear();
 430
 431   // Create a winning group.
 432   trial->AppendGroup("Winner", 10);
 433   // Finalize the group selection by accessing the selected group.
 434   trial->group();
 435   FieldTrialList::AllStatesToString(&save_string);
 436   EXPECT_EQ("*Some name/Winner/", save_string);
 437   save_string.clear();
 438
 439   // Create a second trial and winning group.
 440   scoped_refptr<FieldTrial> trial2 =
 441       CreateFieldTrial("xxx", 10, "Default xxx", NULL);
 442   trial2->AppendGroup("yyyy", 10);
 443   // Finalize the group selection by accessing the selected group.
 444   trial2->group();
 445
 446   FieldTrialList::AllStatesToString(&save_string);
 447   // We assume names are alphabetized... though this is not critical.
 448   EXPECT_EQ("*Some name/Winner/*xxx/yyyy/", save_string);
 449   save_string.clear();
 450
 451   // Create a third trial with only the default group.
 452   scoped_refptr<FieldTrial> trial3 =
 453       CreateFieldTrial("zzz", 10, "default", NULL);
 454
 455   FieldTrialList::AllStatesToString(&save_string);
 456   EXPECT_EQ("*Some name/Winner/*xxx/yyyy/zzz/default/", save_string);
 457 }
 458
 459 TEST_F(FieldTrialTest, Restore) {
 460   ASSERT_FALSE(FieldTrialList::TrialExists("Some_name"));
 461   ASSERT_FALSE(FieldTrialList::TrialExists("xxx"));
 462
 463   FieldTrialList::CreateTrialsFromString("Some_name/Winner/xxx/yyyy/",
 464                                          FieldTrialList::DONT_ACTIVATE_TRIALS,
 465                                          std::set<std::string>());
 466
 467   FieldTrial* trial = FieldTrialList::Find("Some_name");
 468   ASSERT_NE(static_cast<FieldTrial*>(NULL), trial);
 469   EXPECT_EQ("Winner", trial->group_name());
 470   EXPECT_EQ("Some_name", trial->trial_name());
 471
 472   trial = FieldTrialList::Find("xxx");
 473   ASSERT_NE(static_cast<FieldTrial*>(NULL), trial);
 474   EXPECT_EQ("yyyy", trial->group_name());
 475   EXPECT_EQ("xxx", trial->trial_name());
 476 }
 477
 478 TEST_F(FieldTrialTest, RestoreNotEndingWithSlash) {
 479   EXPECT_TRUE(FieldTrialList::CreateTrialsFromString(
 480       "tname/gname", FieldTrialList::DONT_ACTIVATE_TRIALS,
 481       std::set<std::string>()));
 482
 483   FieldTrial* trial = FieldTrialList::Find("tname");
 484   ASSERT_NE(static_cast<FieldTrial*>(NULL), trial);
 485   EXPECT_EQ("gname", trial->group_name());
 486   EXPECT_EQ("tname", trial->trial_name());
 487 }
 488
 489 TEST_F(FieldTrialTest, BogusRestore) {
 490   EXPECT_FALSE(FieldTrialList::CreateTrialsFromString(
 491       "MissingSlash", FieldTrialList::DONT_ACTIVATE_TRIALS,
 492       std::set<std::string>()));
 493   EXPECT_FALSE(FieldTrialList::CreateTrialsFromString(
 494       "MissingGroupName/", FieldTrialList::DONT_ACTIVATE_TRIALS,
 495       std::set<std::string>()));
 496   EXPECT_FALSE(FieldTrialList::CreateTrialsFromString(
 497       "noname, only group/", FieldTrialList::DONT_ACTIVATE_TRIALS,
 498       std::set<std::string>()));
 499   EXPECT_FALSE(FieldTrialList::CreateTrialsFromString(
 500       "/emptyname", FieldTrialList::DONT_ACTIVATE_TRIALS,
 501       std::set<std::string>()));
 502   EXPECT_FALSE(FieldTrialList::CreateTrialsFromString(
 503       "*/emptyname", FieldTrialList::DONT_ACTIVATE_TRIALS,
 504       std::set<std::string>()));
 505 }
 506
 507 TEST_F(FieldTrialTest, DuplicateRestore) {
 508   scoped_refptr<FieldTrial> trial =
 509       CreateFieldTrial("Some name", 10, "Default", NULL);
 510   trial->AppendGroup("Winner", 10);
 511   // Finalize the group selection by accessing the selected group.
 512   trial->group();
 513   std::string save_string;
 514   FieldTrialList::StatesToString(&save_string);
 515   EXPECT_EQ("Some name/Winner/", save_string);
 516
 517   // It is OK if we redundantly specify a winner.
 518   EXPECT_TRUE(FieldTrialList::CreateTrialsFromString(
 519       save_string, FieldTrialList::DONT_ACTIVATE_TRIALS,
 520       std::set<std::string>()));
 521
 522   // But it is an error to try to change to a different winner.
 523   EXPECT_FALSE(FieldTrialList::CreateTrialsFromString(
 524       "Some name/Loser/", FieldTrialList::DONT_ACTIVATE_TRIALS,
 525       std::set<std::string>()));
 526 }
 527
 528 TEST_F(FieldTrialTest, CreateTrialsFromStringActive) {
 529   ASSERT_FALSE(FieldTrialList::TrialExists("Abc"));
 530   ASSERT_FALSE(FieldTrialList::TrialExists("Xyz"));
 531   ASSERT_TRUE(FieldTrialList::CreateTrialsFromString(
 532       "Abc/def/Xyz/zyx/", FieldTrialList::ACTIVATE_TRIALS,
 533       std::set<std::string>()));
 534
 535   FieldTrial::ActiveGroups active_groups;
 536   FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
 537   ASSERT_EQ(2U, active_groups.size());
 538   EXPECT_EQ("Abc", active_groups[0].trial_name);
 539   EXPECT_EQ("def", active_groups[0].group_name);
 540   EXPECT_EQ("Xyz", active_groups[1].trial_name);
 541   EXPECT_EQ("zyx", active_groups[1].group_name);
 542 }
 543
 544 TEST_F(FieldTrialTest, CreateTrialsFromStringNotActive) {
 545   ASSERT_FALSE(FieldTrialList::TrialExists("Abc"));
 546   ASSERT_FALSE(FieldTrialList::TrialExists("Xyz"));
 547   ASSERT_TRUE(FieldTrialList::CreateTrialsFromString(
 548       "Abc/def/Xyz/zyx/", FieldTrialList::DONT_ACTIVATE_TRIALS,
 549       std::set<std::string>()));
 550
 551   FieldTrial::ActiveGroups active_groups;
 552   FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
 553   ASSERT_TRUE(active_groups.empty());
 554
 555   // Check that the values still get returned and querying them activates them.
 556   EXPECT_EQ("def", FieldTrialList::FindFullName("Abc"));
 557   EXPECT_EQ("zyx", FieldTrialList::FindFullName("Xyz"));
 558
 559   FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
 560   ASSERT_EQ(2U, active_groups.size());
 561   EXPECT_EQ("Abc", active_groups[0].trial_name);
 562   EXPECT_EQ("def", active_groups[0].group_name);
 563   EXPECT_EQ("Xyz", active_groups[1].trial_name);
 564   EXPECT_EQ("zyx", active_groups[1].group_name);
 565 }
 566
 567 TEST_F(FieldTrialTest, CreateTrialsFromStringForceActivation) {
 568   ASSERT_FALSE(FieldTrialList::TrialExists("Abc"));
 569   ASSERT_FALSE(FieldTrialList::TrialExists("def"));
 570   ASSERT_FALSE(FieldTrialList::TrialExists("Xyz"));
 571   ASSERT_TRUE(FieldTrialList::CreateTrialsFromString(
 572       "*Abc/cba/def/fed/*Xyz/zyx/", FieldTrialList::DONT_ACTIVATE_TRIALS,
 573       std::set<std::string>()));
 574
 575   FieldTrial::ActiveGroups active_groups;
 576   FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
 577   ASSERT_EQ(2U, active_groups.size());
 578   EXPECT_EQ("Abc", active_groups[0].trial_name);
 579   EXPECT_EQ("cba", active_groups[0].group_name);
 580   EXPECT_EQ("Xyz", active_groups[1].trial_name);
 581   EXPECT_EQ("zyx", active_groups[1].group_name);
 582 }
 583
 584 TEST_F(FieldTrialTest, CreateTrialsFromStringActiveObserver) {
 585   ASSERT_FALSE(FieldTrialList::TrialExists("Abc"));
 586
 587   TestFieldTrialObserver observer;
 588   ASSERT_TRUE(FieldTrialList::CreateTrialsFromString(
 589       "Abc/def/", FieldTrialList::ACTIVATE_TRIALS, std::set<std::string>()));
 590
 591   RunLoop().RunUntilIdle();
 592   EXPECT_EQ("Abc", observer.trial_name());
 593   EXPECT_EQ("def", observer.group_name());
 594 }
 595
 596 TEST_F(FieldTrialTest, CreateTrialsFromStringNotActiveObserver) {
 597   ASSERT_FALSE(FieldTrialList::TrialExists("Abc"));
 598
 599   TestFieldTrialObserver observer;
 600   ASSERT_TRUE(FieldTrialList::CreateTrialsFromString(
 601       "Abc/def/", FieldTrialList::DONT_ACTIVATE_TRIALS,
 602       std::set<std::string>()));
 603   RunLoop().RunUntilIdle();
 604   // Observer shouldn't be notified.
 605   EXPECT_TRUE(observer.trial_name().empty());
 606
 607   // Check that the values still get returned and querying them activates them.
 608   EXPECT_EQ("def", FieldTrialList::FindFullName("Abc"));
 609
 610   RunLoop().RunUntilIdle();
 611   EXPECT_EQ("Abc", observer.trial_name());
 612   EXPECT_EQ("def", observer.group_name());
 613 }
 614
 615 TEST_F(FieldTrialTest, CreateTrialsFromStringWithIgnoredFieldTrials) {
 616   ASSERT_FALSE(FieldTrialList::TrialExists("Unaccepted1"));
 617   ASSERT_FALSE(FieldTrialList::TrialExists("Foo"));
 618   ASSERT_FALSE(FieldTrialList::TrialExists("Unaccepted2"));
 619   ASSERT_FALSE(FieldTrialList::TrialExists("Bar"));
 620   ASSERT_FALSE(FieldTrialList::TrialExists("Unaccepted3"));
 621
 622   std::set<std::string> ignored_trial_names;
 623   ignored_trial_names.insert("Unaccepted1");
 624   ignored_trial_names.insert("Unaccepted2");
 625   ignored_trial_names.insert("Unaccepted3");
 626
 627   FieldTrialList::CreateTrialsFromString(
 628       "Unaccepted1/Unaccepted1_name/"
 629       "Foo/Foo_name/"
 630       "Unaccepted2/Unaccepted2_name/"
 631       "Bar/Bar_name/"
 632       "Unaccepted3/Unaccepted3_name/",
 633       FieldTrialList::DONT_ACTIVATE_TRIALS,
 634       ignored_trial_names);
 635
 636   EXPECT_FALSE(FieldTrialList::TrialExists("Unaccepted1"));
 637   EXPECT_TRUE(FieldTrialList::TrialExists("Foo"));
 638   EXPECT_FALSE(FieldTrialList::TrialExists("Unaccepted2"));
 639   EXPECT_TRUE(FieldTrialList::TrialExists("Bar"));
 640   EXPECT_FALSE(FieldTrialList::TrialExists("Unaccepted3"));
 641
 642   FieldTrial::ActiveGroups active_groups;
 643   FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
 644   EXPECT_TRUE(active_groups.empty());
 645
 646   FieldTrial* trial = FieldTrialList::Find("Foo");
 647   ASSERT_NE(static_cast<FieldTrial*>(NULL), trial);
 648   EXPECT_EQ("Foo", trial->trial_name());
 649   EXPECT_EQ("Foo_name", trial->group_name());
 650
 651   trial = FieldTrialList::Find("Bar");
 652   ASSERT_NE(static_cast<FieldTrial*>(NULL), trial);
 653   EXPECT_EQ("Bar", trial->trial_name());
 654   EXPECT_EQ("Bar_name", trial->group_name());
 655 }
 656
 657 TEST_F(FieldTrialTest, CreateFieldTrial) {
 658   ASSERT_FALSE(FieldTrialList::TrialExists("Some_name"));
 659
 660   FieldTrialList::CreateFieldTrial("Some_name", "Winner");
 661
 662   FieldTrial* trial = FieldTrialList::Find("Some_name");
 663   ASSERT_NE(static_cast<FieldTrial*>(NULL), trial);
 664   EXPECT_EQ("Winner", trial->group_name());
 665   EXPECT_EQ("Some_name", trial->trial_name());
 666 }
 667
 668 TEST_F(FieldTrialTest, CreateFieldTrialIsNotActive) {
 669   const char kTrialName[] = "CreateFieldTrialIsActiveTrial";
 670   const char kWinnerGroup[] = "Winner";
 671   ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
 672   FieldTrialList::CreateFieldTrial(kTrialName, kWinnerGroup);
 673
 674   FieldTrial::ActiveGroups active_groups;
 675   FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
 676   EXPECT_TRUE(active_groups.empty());
 677 }
 678
 679 TEST_F(FieldTrialTest, DuplicateFieldTrial) {
 680   scoped_refptr<FieldTrial> trial =
 681       CreateFieldTrial("Some_name", 10, "Default", NULL);
 682   trial->AppendGroup("Winner", 10);
 683
 684   // It is OK if we redundantly specify a winner.
 685   FieldTrial* trial1 = FieldTrialList::CreateFieldTrial("Some_name", "Winner");
 686   EXPECT_TRUE(trial1 != NULL);
 687
 688   // But it is an error to try to change to a different winner.
 689   FieldTrial* trial2 = FieldTrialList::CreateFieldTrial("Some_name", "Loser");
 690   EXPECT_TRUE(trial2 == NULL);
 691 }
 692
 693 TEST_F(FieldTrialTest, DisableImmediately) {
 694   int default_group_number = -1;
 695   scoped_refptr<FieldTrial> trial =
 696       CreateFieldTrial("trial", 100, "default", &default_group_number);
 697   trial->Disable();
 698   ASSERT_EQ("default", trial->group_name());
 699   ASSERT_EQ(default_group_number, trial->group());
 700 }
 701
 702 TEST_F(FieldTrialTest, DisableAfterInitialization) {
 703   scoped_refptr<FieldTrial> trial =
 704       CreateFieldTrial("trial", 100, "default", NULL);
 705   trial->AppendGroup("non_default", 100);
 706   trial->Disable();
 707   ASSERT_EQ("default", trial->group_name());
 708 }
 709
 710 TEST_F(FieldTrialTest, ForcedFieldTrials) {
 711   // Validate we keep the forced choice.
 712   FieldTrial* forced_trial = FieldTrialList::CreateFieldTrial("Use the",
 713                                                               "Force");
 714   EXPECT_STREQ("Force", forced_trial->group_name().c_str());
 715
 716   int default_group_number = -1;
 717   scoped_refptr<FieldTrial> factory_trial =
 718       CreateFieldTrial("Use the", 1000, "default", &default_group_number);
 719   EXPECT_EQ(factory_trial.get(), forced_trial);
 720
 721   int chosen_group = factory_trial->AppendGroup("Force", 100);
 722   EXPECT_EQ(chosen_group, factory_trial->group());
 723   int not_chosen_group = factory_trial->AppendGroup("Dark Side", 100);
 724   EXPECT_NE(chosen_group, not_chosen_group);
 725
 726   // Since we didn't force the default group, we should not be returned the
 727   // chosen group as the default group.
 728   EXPECT_NE(default_group_number, chosen_group);
 729   int new_group = factory_trial->AppendGroup("Duck Tape", 800);
 730   EXPECT_NE(chosen_group, new_group);
 731   // The new group should not be the default group either.
 732   EXPECT_NE(default_group_number, new_group);
 733 }
 734
 735 TEST_F(FieldTrialTest, ForcedFieldTrialsDefaultGroup) {
 736   // Forcing the default should use the proper group ID.
 737   FieldTrial* forced_trial = FieldTrialList::CreateFieldTrial("Trial Name",
 738                                                               "Default");
 739   int default_group_number = -1;
 740   scoped_refptr<FieldTrial> factory_trial =
 741       CreateFieldTrial("Trial Name", 1000, "Default", &default_group_number);
 742   EXPECT_EQ(forced_trial, factory_trial.get());
 743
 744   int other_group = factory_trial->AppendGroup("Not Default", 100);
 745   EXPECT_STREQ("Default", factory_trial->group_name().c_str());
 746   EXPECT_EQ(default_group_number, factory_trial->group());
 747   EXPECT_NE(other_group, factory_trial->group());
 748
 749   int new_other_group = factory_trial->AppendGroup("Not Default Either", 800);
 750   EXPECT_NE(new_other_group, factory_trial->group());
 751 }
 752
 753 TEST_F(FieldTrialTest, SetForced) {
 754   // Start by setting a trial for which we ensure a winner...
 755   int default_group_number = -1;
 756   scoped_refptr<FieldTrial> forced_trial =
 757       CreateFieldTrial("Use the", 1, "default", &default_group_number);
 758   EXPECT_EQ(forced_trial, forced_trial);
 759
 760   int forced_group = forced_trial->AppendGroup("Force", 1);
 761   EXPECT_EQ(forced_group, forced_trial->group());
 762
 763   // Now force it.
 764   forced_trial->SetForced();
 765
 766   // Now try to set it up differently as a hard coded registration would.
 767   scoped_refptr<FieldTrial> hard_coded_trial =
 768       CreateFieldTrial("Use the", 1, "default", &default_group_number);
 769   EXPECT_EQ(hard_coded_trial, forced_trial);
 770
 771   int would_lose_group = hard_coded_trial->AppendGroup("Force", 0);
 772   EXPECT_EQ(forced_group, hard_coded_trial->group());
 773   EXPECT_EQ(forced_group, would_lose_group);
 774
 775   // Same thing if we would have done it to win again.
 776   scoped_refptr<FieldTrial> other_hard_coded_trial =
 777       CreateFieldTrial("Use the", 1, "default", &default_group_number);
 778   EXPECT_EQ(other_hard_coded_trial, forced_trial);
 779
 780   int would_win_group = other_hard_coded_trial->AppendGroup("Force", 1);
 781   EXPECT_EQ(forced_group, other_hard_coded_trial->group());
 782   EXPECT_EQ(forced_group, would_win_group);
 783 }
 784
 785 TEST_F(FieldTrialTest, SetForcedDefaultOnly) {
 786   const char kTrialName[] = "SetForcedDefaultOnly";
 787   ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
 788
 789   int default_group = -1;
 790   scoped_refptr<FieldTrial> trial =
 791       CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
 792   trial->SetForced();
 793
 794   trial = CreateFieldTrial(kTrialName, 100, kDefaultGroupName, NULL);
 795   EXPECT_EQ(default_group, trial->group());
 796   EXPECT_EQ(kDefaultGroupName, trial->group_name());
 797 }
 798
 799 TEST_F(FieldTrialTest, SetForcedDefaultWithExtraGroup) {
 800   const char kTrialName[] = "SetForcedDefaultWithExtraGroup";
 801   ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
 802
 803   int default_group = -1;
 804   scoped_refptr<FieldTrial> trial =
 805       CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
 806   trial->SetForced();
 807
 808   trial = CreateFieldTrial(kTrialName, 100, kDefaultGroupName, NULL);
 809   const int extra_group = trial->AppendGroup("Extra", 100);
 810   EXPECT_EQ(default_group, trial->group());
 811   EXPECT_NE(extra_group, trial->group());
 812   EXPECT_EQ(kDefaultGroupName, trial->group_name());
 813 }
 814
 815 TEST_F(FieldTrialTest, SetForcedTurnFeatureOn) {
 816   const char kTrialName[] = "SetForcedTurnFeatureOn";
 817   const char kExtraGroupName[] = "Extra";
 818   ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
 819
 820   // Simulate a server-side (forced) config that turns the feature on when the
 821   // original hard-coded config had it disabled.
 822   scoped_refptr<FieldTrial> forced_trial =
 823       CreateFieldTrial(kTrialName, 100, kDefaultGroupName, NULL);
 824   forced_trial->AppendGroup(kExtraGroupName, 100);
 825   forced_trial->SetForced();
 826
 827   int default_group = -1;
 828   scoped_refptr<FieldTrial> client_trial =
 829       CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
 830   const int extra_group = client_trial->AppendGroup(kExtraGroupName, 0);
 831   EXPECT_NE(default_group, extra_group);
 832
 833   EXPECT_FALSE(client_trial->group_reported_);
 834   EXPECT_EQ(extra_group, client_trial->group());
 835   EXPECT_TRUE(client_trial->group_reported_);
 836   EXPECT_EQ(kExtraGroupName, client_trial->group_name());
 837 }
 838
 839 TEST_F(FieldTrialTest, SetForcedTurnFeatureOff) {
 840   const char kTrialName[] = "SetForcedTurnFeatureOff";
 841   const char kExtraGroupName[] = "Extra";
 842   ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
 843
 844   // Simulate a server-side (forced) config that turns the feature off when the
 845   // original hard-coded config had it enabled.
 846   scoped_refptr<FieldTrial> forced_trial =
 847       CreateFieldTrial(kTrialName, 100, kDefaultGroupName, NULL);
 848   forced_trial->AppendGroup(kExtraGroupName, 0);
 849   forced_trial->SetForced();
 850
 851   int default_group = -1;
 852   scoped_refptr<FieldTrial> client_trial =
 853       CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
 854   const int extra_group = client_trial->AppendGroup(kExtraGroupName, 100);
 855   EXPECT_NE(default_group, extra_group);
 856
 857   EXPECT_FALSE(client_trial->group_reported_);
 858   EXPECT_EQ(default_group, client_trial->group());
 859   EXPECT_TRUE(client_trial->group_reported_);
 860   EXPECT_EQ(kDefaultGroupName, client_trial->group_name());
 861 }
 862
 863 TEST_F(FieldTrialTest, SetForcedChangeDefault_Default) {
 864   const char kTrialName[] = "SetForcedDefaultGroupChange";
 865   const char kGroupAName[] = "A";
 866   const char kGroupBName[] = "B";
 867   ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
 868
 869   // Simulate a server-side (forced) config that switches which group is default
 870   // and ensures that the non-forced code receives the correct group numbers.
 871   scoped_refptr<FieldTrial> forced_trial =
 872       CreateFieldTrial(kTrialName, 100, kGroupAName, NULL);
 873   forced_trial->AppendGroup(kGroupBName, 100);
 874   forced_trial->SetForced();
 875
 876   int default_group = -1;
 877   scoped_refptr<FieldTrial> client_trial =
 878       CreateFieldTrial(kTrialName, 100, kGroupBName, &default_group);
 879   const int extra_group = client_trial->AppendGroup(kGroupAName, 50);
 880   EXPECT_NE(default_group, extra_group);
 881
 882   EXPECT_FALSE(client_trial->group_reported_);
 883   EXPECT_EQ(default_group, client_trial->group());
 884   EXPECT_TRUE(client_trial->group_reported_);
 885   EXPECT_EQ(kGroupBName, client_trial->group_name());
 886 }
 887
 888 TEST_F(FieldTrialTest, SetForcedChangeDefault_NonDefault) {
 889   const char kTrialName[] = "SetForcedDefaultGroupChange";
 890   const char kGroupAName[] = "A";
 891   const char kGroupBName[] = "B";
 892   ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
 893
 894   // Simulate a server-side (forced) config that switches which group is default
 895   // and ensures that the non-forced code receives the correct group numbers.
 896   scoped_refptr<FieldTrial> forced_trial =
 897       CreateFieldTrial(kTrialName, 100, kGroupAName, NULL);
 898   forced_trial->AppendGroup(kGroupBName, 0);
 899   forced_trial->SetForced();
 900
 901   int default_group = -1;
 902   scoped_refptr<FieldTrial> client_trial =
 903       CreateFieldTrial(kTrialName, 100, kGroupBName, &default_group);
 904   const int extra_group = client_trial->AppendGroup(kGroupAName, 50);
 905   EXPECT_NE(default_group, extra_group);
 906
 907   EXPECT_FALSE(client_trial->group_reported_);
 908   EXPECT_EQ(extra_group, client_trial->group());
 909   EXPECT_TRUE(client_trial->group_reported_);
 910   EXPECT_EQ(kGroupAName, client_trial->group_name());
 911 }
 912
 913 TEST_F(FieldTrialTest, Observe) {
 914   const char kTrialName[] = "TrialToObserve1";
 915   const char kSecondaryGroupName[] = "SecondaryGroup";
 916
 917   TestFieldTrialObserver observer;
 918   int default_group = -1;
 919   scoped_refptr<FieldTrial> trial =
 920       CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
 921   const int secondary_group = trial->AppendGroup(kSecondaryGroupName, 50);
 922   const int chosen_group = trial->group();
 923   EXPECT_TRUE(chosen_group == default_group || chosen_group == secondary_group);
 924
 925   RunLoop().RunUntilIdle();
 926   EXPECT_EQ(kTrialName, observer.trial_name());
 927   if (chosen_group == default_group)
 928     EXPECT_EQ(kDefaultGroupName, observer.group_name());
 929   else
 930     EXPECT_EQ(kSecondaryGroupName, observer.group_name());
 931 }
 932
 933 TEST_F(FieldTrialTest, ObserveDisabled) {
 934   const char kTrialName[] = "TrialToObserve2";
 935
 936   TestFieldTrialObserver observer;
 937   int default_group = -1;
 938   scoped_refptr<FieldTrial> trial =
 939       CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
 940   trial->AppendGroup("A", 25);
 941   trial->AppendGroup("B", 25);
 942   trial->AppendGroup("C", 25);
 943   trial->Disable();
 944
 945   // Observer shouldn't be notified of a disabled trial.
 946   RunLoop().RunUntilIdle();
 947   EXPECT_TRUE(observer.trial_name().empty());
 948   EXPECT_TRUE(observer.group_name().empty());
 949
 950   // Observer shouldn't be notified even after a |group()| call.
 951   EXPECT_EQ(default_group, trial->group());
 952   RunLoop().RunUntilIdle();
 953   EXPECT_TRUE(observer.trial_name().empty());
 954   EXPECT_TRUE(observer.group_name().empty());
 955 }
 956
 957 TEST_F(FieldTrialTest, ObserveForcedDisabled) {
 958   const char kTrialName[] = "TrialToObserve3";
 959
 960   TestFieldTrialObserver observer;
 961   int default_group = -1;
 962   scoped_refptr<FieldTrial> trial =
 963       CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
 964   trial->AppendGroup("A", 25);
 965   trial->AppendGroup("B", 25);
 966   trial->AppendGroup("C", 25);
 967   trial->SetForced();
 968   trial->Disable();
 969
 970   // Observer shouldn't be notified of a disabled trial, even when forced.
 971   RunLoop().RunUntilIdle();
 972   EXPECT_TRUE(observer.trial_name().empty());
 973   EXPECT_TRUE(observer.group_name().empty());
 974
 975   // Observer shouldn't be notified even after a |group()| call.
 976   EXPECT_EQ(default_group, trial->group());
 977   RunLoop().RunUntilIdle();
 978   EXPECT_TRUE(observer.trial_name().empty());
 979   EXPECT_TRUE(observer.group_name().empty());
 980 }
 981
 982 TEST_F(FieldTrialTest, DisabledTrialNotActive) {
 983   const char kTrialName[] = "DisabledTrial";
 984   ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
 985
 986   scoped_refptr<FieldTrial> trial =
 987       CreateFieldTrial(kTrialName, 100, kDefaultGroupName, NULL);
 988   trial->AppendGroup("X", 50);
 989   trial->Disable();
 990
 991   // Ensure the trial is not listed as active.
 992   FieldTrial::ActiveGroups active_groups;
 993   FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
 994   EXPECT_TRUE(active_groups.empty());
 995
 996   // Ensure the trial is not listed in the |StatesToString()| result.
 997   std::string states;
 998   FieldTrialList::StatesToString(&states);
 999   EXPECT_TRUE(states.empty());
1000 }
1001
1002 TEST_F(FieldTrialTest, ExpirationYearNotExpired) {
1003   const char kTrialName[] = "NotExpired";
1004   const char kGroupName[] = "Group2";
1005   const int kProbability = 100;
1006   ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
1007
1008   scoped_refptr<FieldTrial> trial =
1009       CreateFieldTrial(kTrialName, kProbability, kDefaultGroupName, NULL);
1010   trial->AppendGroup(kGroupName, kProbability);
1011   EXPECT_EQ(kGroupName, trial->group_name());
1012 }
1013
1014 TEST_F(FieldTrialTest, FloatBoundariesGiveEqualGroupSizes) {
1015   const int kBucketCount = 100;
1016
1017   // Try each boundary value |i / 100.0| as the entropy value.
1018   for (int i = 0; i < kBucketCount; ++i) {
1019     const double entropy = i / static_cast<double>(kBucketCount);
1020
1021     scoped_refptr<base::FieldTrial> trial(
1022         new base::FieldTrial("test", kBucketCount, "default", entropy));
1023     for (int j = 0; j < kBucketCount; ++j)
1024       trial->AppendGroup(base::IntToString(j), 1);
1025
1026     EXPECT_EQ(base::IntToString(i), trial->group_name());
1027   }
1028 }
1029
1030 TEST_F(FieldTrialTest, DoesNotSurpassTotalProbability) {
1031   const double kEntropyValue = 1.0 - 1e-9;
1032   ASSERT_LT(kEntropyValue, 1.0);
1033
1034   scoped_refptr<base::FieldTrial> trial(
1035       new base::FieldTrial("test", 2, "default", kEntropyValue));
1036   trial->AppendGroup("1", 1);
1037   trial->AppendGroup("2", 1);
1038
1039   EXPECT_EQ("2", trial->group_name());
1040 }
1041
1042 TEST_F(FieldTrialTest, CreateSimulatedFieldTrial) {
1043   const char kTrialName[] = "CreateSimulatedFieldTrial";
1044   ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
1045
1046   // Different cases to test, e.g. default vs. non default group being chosen.
1047   struct {
1048     double entropy_value;
1049     const char* expected_group;
1050   } test_cases[] = {
1051     { 0.4, "A" },
1052     { 0.85, "B" },
1053     { 0.95, kDefaultGroupName },
1054   };
1055
1056   for (size_t i = 0; i < arraysize(test_cases); ++i) {
1057     TestFieldTrialObserver observer;
1058     scoped_refptr<FieldTrial> trial(
1059        FieldTrial::CreateSimulatedFieldTrial(kTrialName, 100, kDefaultGroupName,
1060                                              test_cases[i].entropy_value));
1061     trial->AppendGroup("A", 80);
1062     trial->AppendGroup("B", 10);
1063     EXPECT_EQ(test_cases[i].expected_group, trial->group_name());
1064
1065     // Field trial shouldn't have been registered with the list.
1066     EXPECT_FALSE(FieldTrialList::TrialExists(kTrialName));
1067     EXPECT_EQ(0u, FieldTrialList::GetFieldTrialCount());
1068
1069     // Observer shouldn't have been notified.
1070     RunLoop().RunUntilIdle();
1071     EXPECT_TRUE(observer.trial_name().empty());
1072
1073     // The trial shouldn't be in the active set of trials.
1074     FieldTrial::ActiveGroups active_groups;
1075     FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
1076     EXPECT_TRUE(active_groups.empty());
1077
1078     // The trial shouldn't be listed in the |StatesToString()| result.
1079     std::string states;
1080     FieldTrialList::StatesToString(&states);
1081     EXPECT_TRUE(states.empty());
1082   }
1083 }
1084
1085 TEST(FieldTrialTestWithoutList, StatesStringFormat) {
1086   std::string save_string;
1087
1088   // Scoping the first FieldTrialList, as we need another one to test the
1089   // importing function.
1090   {
1091     FieldTrialList field_trial_list(NULL);
1092     scoped_refptr<FieldTrial> trial =
1093         CreateFieldTrial("Abc", 10, "Default some name", NULL);
1094     trial->AppendGroup("cba", 10);
1095     trial->group();
1096     scoped_refptr<FieldTrial> trial2 =
1097         CreateFieldTrial("Xyz", 10, "Default xxx", NULL);
1098     trial2->AppendGroup("zyx", 10);
1099     trial2->group();
1100     scoped_refptr<FieldTrial> trial3 =
1101         CreateFieldTrial("zzz", 10, "default", NULL);
1102
1103     FieldTrialList::AllStatesToString(&save_string);
1104   }
1105
1106   // Starting with a new blank FieldTrialList.
1107   FieldTrialList field_trial_list(NULL);
1108   ASSERT_TRUE(field_trial_list.CreateTrialsFromString(
1109       save_string, FieldTrialList::DONT_ACTIVATE_TRIALS,
1110       std::set<std::string>()));
1111
1112   FieldTrial::ActiveGroups active_groups;
1113   field_trial_list.GetActiveFieldTrialGroups(&active_groups);
1114   ASSERT_EQ(2U, active_groups.size());
1115   EXPECT_EQ("Abc", active_groups[0].trial_name);
1116   EXPECT_EQ("cba", active_groups[0].group_name);
1117   EXPECT_EQ("Xyz", active_groups[1].trial_name);
1118   EXPECT_EQ("zyx", active_groups[1].group_name);
1119   EXPECT_TRUE(field_trial_list.TrialExists("zzz"));
1120 }
1121
1122 #if GTEST_HAS_DEATH_TEST
1123 TEST(FieldTrialDeathTest, OneTimeRandomizedTrialWithoutFieldTrialList) {
1124   // Trying to instantiate a one-time randomized field trial before the
1125   // FieldTrialList is created should crash.
1126   EXPECT_DEATH(FieldTrialList::FactoryGetFieldTrial(
1127       "OneTimeRandomizedTrialWithoutFieldTrialList", 100, kDefaultGroupName,
1128       base::FieldTrialList::kNoExpirationYear, 1, 1,
1129       base::FieldTrial::ONE_TIME_RANDOMIZED, NULL), "");
1130 }
1131 #endif
1132
1133 }  // namespace base