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 <stddef.h>
8 #include <utility>
9
10 #include "base/base_switches.h"
11 #include "base/build_time.h"
12 #include "base/feature_list.h"
13 #include "base/memory/ptr_util.h"
14 #include "base/metrics/field_trial_param_associator.h"
15 #include "base/rand_util.h"
16 #include "base/run_loop.h"
17 #include "base/stl_util.h"
18 #include "base/strings/string_number_conversions.h"
19 #include "base/strings/stringprintf.h"
20 #include "base/test/gtest_util.h"
21 #include "base/test/mock_entropy_provider.h"
22 #include "base/test/multiprocess_test.h"
23 #include "base/test/scoped_feature_list.h"
24 #include "base/test/scoped_field_trial_list_resetter.h"
25 #include "base/test/task_environment.h"
26 #include "base/test/test_shared_memory_util.h"
27 #include "base/test/test_timeouts.h"
28 #include "build/build_config.h"
29 #include "testing/gtest/include/gtest/gtest.h"
30 #include "testing/multiprocess_func_list.h"
31
32 #if defined(OS_ANDROID)
33 #include "base/posix/global_descriptors.h"
34 #endif
35
36 #if defined(OS_MAC)
37 #include "base/mac/mach_port_rendezvous.h"
38 #endif
39
40 namespace base {
41
42 namespace {
43
44 // Default group name used by several tests.
45 const char kDefaultGroupName[] = "DefaultGroup";
46
47 // Call FieldTrialList::FactoryGetFieldTrial().
CreateFieldTrial(const std::string & trial_name,int total_probability,const std::string & default_group_name,int * default_group_number)48 scoped_refptr<FieldTrial> CreateFieldTrial(
49 const std::string& trial_name,
50 int total_probability,
51 const std::string& default_group_name,
52 int* default_group_number) {
53 return FieldTrialList::FactoryGetFieldTrial(
54 trial_name, total_probability, default_group_name,
55 FieldTrial::SESSION_RANDOMIZED, default_group_number);
56 }
57
58 // FieldTrialList::Observer implementation for testing.
59 class TestFieldTrialObserver : public FieldTrialList::Observer {
60 public:
61 enum Type {
62 ASYNCHRONOUS,
63 SYNCHRONOUS,
64 };
65
TestFieldTrialObserver(Type type)66 explicit TestFieldTrialObserver(Type type) : type_(type) {
67 if (type == SYNCHRONOUS)
68 FieldTrialList::SetSynchronousObserver(this);
69 else
70 FieldTrialList::AddObserver(this);
71 }
72 TestFieldTrialObserver(const TestFieldTrialObserver&) = delete;
73 TestFieldTrialObserver& operator=(const TestFieldTrialObserver&) = delete;
74
~TestFieldTrialObserver()75 ~TestFieldTrialObserver() override {
76 if (type_ == SYNCHRONOUS)
77 FieldTrialList::RemoveSynchronousObserver(this);
78 else
79 FieldTrialList::RemoveObserver(this);
80 }
81
OnFieldTrialGroupFinalized(const std::string & trial,const std::string & group)82 void OnFieldTrialGroupFinalized(const std::string& trial,
83 const std::string& group) override {
84 trial_name_ = trial;
85 group_name_ = group;
86 }
87
trial_name() const88 const std::string& trial_name() const { return trial_name_; }
group_name() const89 const std::string& group_name() const { return group_name_; }
90
91 private:
92 const Type type_;
93 std::string trial_name_;
94 std::string group_name_;
95 };
96
MockEscapeQueryParamValue(const std::string & input)97 std::string MockEscapeQueryParamValue(const std::string& input) {
98 return input;
99 }
100
101 } // namespace
102
103 class FieldTrialTest : public ::testing::Test {
104 public:
FieldTrialTest()105 FieldTrialTest() : trial_list_(nullptr) {}
106 FieldTrialTest(const FieldTrialTest&) = delete;
107 FieldTrialTest& operator=(const FieldTrialTest&) = delete;
108
109 private:
110 test::TaskEnvironment task_environment_;
111 // The test suite instantiates a FieldTrialList but for the purpose of these
112 // tests it's cleaner to start from scratch.
113 test::ScopedFieldTrialListResetter trial_list_resetter_;
114 FieldTrialList trial_list_;
115 };
116
117 // Test registration, and also check that destructors are called for trials.
TEST_F(FieldTrialTest,Registration)118 TEST_F(FieldTrialTest, Registration) {
119 const char name1[] = "name 1 test";
120 const char name2[] = "name 2 test";
121 EXPECT_FALSE(FieldTrialList::Find(name1));
122 EXPECT_FALSE(FieldTrialList::Find(name2));
123
124 scoped_refptr<FieldTrial> trial1 =
125 CreateFieldTrial(name1, 10, "default name 1 test", nullptr);
126 EXPECT_EQ(FieldTrial::kNotFinalized, trial1->group_);
127 EXPECT_EQ(name1, trial1->trial_name());
128 EXPECT_EQ("", trial1->group_name_internal());
129
130 trial1->AppendGroup(std::string(), 7);
131
132 EXPECT_EQ(trial1.get(), FieldTrialList::Find(name1));
133 EXPECT_FALSE(FieldTrialList::Find(name2));
134
135 scoped_refptr<FieldTrial> trial2 =
136 CreateFieldTrial(name2, 10, "default name 2 test", nullptr);
137 EXPECT_EQ(FieldTrial::kNotFinalized, trial2->group_);
138 EXPECT_EQ(name2, trial2->trial_name());
139 EXPECT_EQ("", trial2->group_name_internal());
140
141 trial2->AppendGroup("a first group", 7);
142
143 EXPECT_EQ(trial1.get(), FieldTrialList::Find(name1));
144 EXPECT_EQ(trial2.get(), FieldTrialList::Find(name2));
145 // Note: FieldTrialList should delete the objects at shutdown.
146 }
147
TEST_F(FieldTrialTest,AbsoluteProbabilities)148 TEST_F(FieldTrialTest, AbsoluteProbabilities) {
149 char always_true[] = " always true";
150 char default_always_true[] = " default always true";
151 char always_false[] = " always false";
152 char default_always_false[] = " default always false";
153 for (int i = 1; i < 250; ++i) {
154 // Try lots of names, by changing the first character of the name.
155 char c = static_cast<char>(i);
156 always_true[0] = c;
157 default_always_true[0] = c;
158 always_false[0] = c;
159 default_always_false[0] = c;
160
161 scoped_refptr<FieldTrial> trial_true =
162 CreateFieldTrial(always_true, 10, default_always_true, nullptr);
163 const std::string winner = "TheWinner";
164 int winner_group = trial_true->AppendGroup(winner, 10);
165
166 EXPECT_EQ(winner_group, trial_true->group());
167 EXPECT_EQ(winner, trial_true->group_name());
168
169 scoped_refptr<FieldTrial> trial_false =
170 CreateFieldTrial(always_false, 10, default_always_false, nullptr);
171 int loser_group = trial_false->AppendGroup("ALoser", 0);
172
173 EXPECT_NE(loser_group, trial_false->group());
174 }
175 }
176
TEST_F(FieldTrialTest,RemainingProbability)177 TEST_F(FieldTrialTest, RemainingProbability) {
178 // First create a test that hasn't had a winner yet.
179 const std::string winner = "Winner";
180 const std::string loser = "Loser";
181 scoped_refptr<FieldTrial> trial;
182 int counter = 0;
183 int default_group_number = -1;
184 do {
185 std::string name = StringPrintf("trial%d", ++counter);
186 trial = CreateFieldTrial(name, 10, winner, &default_group_number);
187 trial->AppendGroup(loser, 5); // 50% chance of not being chosen.
188 // If a group is not assigned, group_ will be kNotFinalized.
189 } while (trial->group_ != FieldTrial::kNotFinalized);
190
191 // And that 'default' group (winner) should always win.
192 EXPECT_EQ(default_group_number, trial->group());
193
194 // And that winner should ALWAYS win.
195 EXPECT_EQ(winner, trial->group_name());
196 }
197
TEST_F(FieldTrialTest,FiftyFiftyProbability)198 TEST_F(FieldTrialTest, FiftyFiftyProbability) {
199 // Check that even with small divisors, we have the proper probabilities, and
200 // all outcomes are possible. Since this is a 50-50 test, it should get both
201 // outcomes in a few tries, but we'll try no more than 100 times (and be flaky
202 // with probability around 1 in 2^99).
203 bool first_winner = false;
204 bool second_winner = false;
205 int counter = 0;
206 do {
207 std::string name = StringPrintf("FiftyFifty%d", ++counter);
208 std::string default_group_name =
209 StringPrintf("Default FiftyFifty%d", ++counter);
210 scoped_refptr<FieldTrial> trial =
211 CreateFieldTrial(name, 2, default_group_name, nullptr);
212 trial->AppendGroup("first", 1); // 50% chance of being chosen.
213 // If group_ is kNotFinalized, then a group assignement hasn't been done.
214 if (trial->group_ != FieldTrial::kNotFinalized) {
215 first_winner = true;
216 continue;
217 }
218 trial->AppendGroup("second", 1); // Always chosen at this point.
219 EXPECT_NE(FieldTrial::kNotFinalized, trial->group());
220 second_winner = true;
221 } while ((!second_winner || !first_winner) && counter < 100);
222 EXPECT_TRUE(second_winner);
223 EXPECT_TRUE(first_winner);
224 }
225
TEST_F(FieldTrialTest,MiddleProbabilities)226 TEST_F(FieldTrialTest, MiddleProbabilities) {
227 char name[] = " same name";
228 char default_group_name[] = " default same name";
229 bool false_event_seen = false;
230 bool true_event_seen = false;
231 for (int i = 1; i < 250; ++i) {
232 char c = static_cast<char>(i);
233 name[0] = c;
234 default_group_name[0] = c;
235 scoped_refptr<FieldTrial> trial =
236 CreateFieldTrial(name, 10, default_group_name, nullptr);
237 int might_win = trial->AppendGroup("MightWin", 5);
238
239 if (trial->group() == might_win) {
240 true_event_seen = true;
241 } else {
242 false_event_seen = true;
243 }
244 if (false_event_seen && true_event_seen)
245 return; // Successful test!!!
246 }
247 // Very surprising to get here. Probability should be around 1 in 2 ** 250.
248 // One of the following will fail.
249 EXPECT_TRUE(false_event_seen);
250 EXPECT_TRUE(true_event_seen);
251 }
252
TEST_F(FieldTrialTest,OneWinner)253 TEST_F(FieldTrialTest, OneWinner) {
254 char name[] = "Some name";
255 char default_group_name[] = "Default some name";
256 int group_count(10);
257
258 int default_group_number = -1;
259 scoped_refptr<FieldTrial> trial =
260 CreateFieldTrial(name, group_count, default_group_name, nullptr);
261 int winner_index(-2);
262 std::string winner_name;
263
264 for (int i = 1; i <= group_count; ++i) {
265 int might_win = trial->AppendGroup(std::string(), 1);
266
267 // Because we keep appending groups, we want to see if the last group that
268 // was added has been assigned or not.
269 if (trial->group_ == might_win) {
270 EXPECT_EQ(-2, winner_index);
271 winner_index = might_win;
272 StringAppendF(&winner_name, "%d", might_win);
273 EXPECT_EQ(winner_name, trial->group_name());
274 }
275 }
276 EXPECT_GE(winner_index, 0);
277 // Since all groups cover the total probability, we should not have
278 // chosen the default group.
279 EXPECT_NE(trial->group(), default_group_number);
280 EXPECT_EQ(trial->group(), winner_index);
281 EXPECT_EQ(trial->group_name(), winner_name);
282 }
283
TEST_F(FieldTrialTest,DisableProbability)284 TEST_F(FieldTrialTest, DisableProbability) {
285 const std::string default_group_name = "Default group";
286 const std::string loser = "Loser";
287 const std::string name = "Trial";
288
289 // Create a field trail that is disabled.
290 int default_group_number = -1;
291 FieldTrial* trial = FieldTrialList::FactoryGetFieldTrial(
292 name, 1000000000, default_group_name, FieldTrial::SESSION_RANDOMIZED,
293 &default_group_number);
294 trial->Disable();
295 trial->AppendGroup(loser, 999999999); // 99.9999999% chance of being chosen.
296
297 // Because trial has expired, we should always be in the default group.
298 EXPECT_EQ(default_group_number, trial->group());
299
300 // And that default_group_name should ALWAYS win.
301 EXPECT_EQ(default_group_name, trial->group_name());
302 }
303
TEST_F(FieldTrialTest,ActiveGroups)304 TEST_F(FieldTrialTest, ActiveGroups) {
305 std::string no_group("No Group");
306 scoped_refptr<FieldTrial> trial =
307 CreateFieldTrial(no_group, 10, "Default", nullptr);
308
309 // There is no winner yet, so no NameGroupId should be returned.
310 FieldTrial::ActiveGroup active_group;
311 EXPECT_FALSE(trial->GetActiveGroup(&active_group));
312
313 // Create a single winning group.
314 std::string one_winner("One Winner");
315 trial = CreateFieldTrial(one_winner, 10, "Default", nullptr);
316 std::string winner("Winner");
317 trial->AppendGroup(winner, 10);
318 EXPECT_FALSE(trial->GetActiveGroup(&active_group));
319 // Finalize the group selection by accessing the selected group.
320 trial->group();
321 EXPECT_TRUE(trial->GetActiveGroup(&active_group));
322 EXPECT_EQ(one_winner, active_group.trial_name);
323 EXPECT_EQ(winner, active_group.group_name);
324
325 std::string multi_group("MultiGroup");
326 scoped_refptr<FieldTrial> multi_group_trial =
327 CreateFieldTrial(multi_group, 9, "Default", nullptr);
328
329 multi_group_trial->AppendGroup("Me", 3);
330 multi_group_trial->AppendGroup("You", 3);
331 multi_group_trial->AppendGroup("Them", 3);
332 EXPECT_FALSE(multi_group_trial->GetActiveGroup(&active_group));
333 // Finalize the group selection by accessing the selected group.
334 multi_group_trial->group();
335 EXPECT_TRUE(multi_group_trial->GetActiveGroup(&active_group));
336 EXPECT_EQ(multi_group, active_group.trial_name);
337 EXPECT_EQ(multi_group_trial->group_name(), active_group.group_name);
338
339 // Now check if the list is built properly...
340 FieldTrial::ActiveGroups active_groups;
341 FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
342 EXPECT_EQ(2U, active_groups.size());
343 for (size_t i = 0; i < active_groups.size(); ++i) {
344 // Order is not guaranteed, so check all values.
345 EXPECT_NE(no_group, active_groups[i].trial_name);
346 EXPECT_TRUE(one_winner != active_groups[i].trial_name ||
347 winner == active_groups[i].group_name);
348 EXPECT_TRUE(multi_group != active_groups[i].trial_name ||
349 multi_group_trial->group_name() == active_groups[i].group_name);
350 }
351 }
352
TEST_F(FieldTrialTest,GetActiveFieldTrialGroupsFromString)353 TEST_F(FieldTrialTest, GetActiveFieldTrialGroupsFromString) {
354 FieldTrial::ActiveGroups active_groups;
355 FieldTrialList::GetActiveFieldTrialGroupsFromString("*A/X/B/Y/*C/Z",
356 &active_groups);
357 ASSERT_EQ(2U, active_groups.size());
358 EXPECT_EQ("A", active_groups[0].trial_name);
359 EXPECT_EQ("X", active_groups[0].group_name);
360 EXPECT_EQ("C", active_groups[1].trial_name);
361 EXPECT_EQ("Z", active_groups[1].group_name);
362 }
363
TEST_F(FieldTrialTest,ActiveGroupsNotFinalized)364 TEST_F(FieldTrialTest, ActiveGroupsNotFinalized) {
365 const char kTrialName[] = "TestTrial";
366 const char kSecondaryGroupName[] = "SecondaryGroup";
367
368 int default_group = -1;
369 scoped_refptr<FieldTrial> trial =
370 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
371 const int secondary_group = trial->AppendGroup(kSecondaryGroupName, 50);
372
373 // Before |group()| is called, |GetActiveGroup()| should return false.
374 FieldTrial::ActiveGroup active_group;
375 EXPECT_FALSE(trial->GetActiveGroup(&active_group));
376
377 // |GetActiveFieldTrialGroups()| should also not include the trial.
378 FieldTrial::ActiveGroups active_groups;
379 FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
380 EXPECT_TRUE(active_groups.empty());
381
382 // After |group()| has been called, both APIs should succeed.
383 const int chosen_group = trial->group();
384 EXPECT_TRUE(chosen_group == default_group || chosen_group == secondary_group);
385
386 EXPECT_TRUE(trial->GetActiveGroup(&active_group));
387 EXPECT_EQ(kTrialName, active_group.trial_name);
388 if (chosen_group == default_group)
389 EXPECT_EQ(kDefaultGroupName, active_group.group_name);
390 else
391 EXPECT_EQ(kSecondaryGroupName, active_group.group_name);
392
393 FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
394 ASSERT_EQ(1U, active_groups.size());
395 EXPECT_EQ(kTrialName, active_groups[0].trial_name);
396 EXPECT_EQ(active_group.group_name, active_groups[0].group_name);
397 }
398
TEST_F(FieldTrialTest,GetGroupNameWithoutActivation)399 TEST_F(FieldTrialTest, GetGroupNameWithoutActivation) {
400 const char kTrialName[] = "TestTrial";
401 const char kSecondaryGroupName[] = "SecondaryGroup";
402
403 int default_group = -1;
404 scoped_refptr<FieldTrial> trial =
405 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
406 trial->AppendGroup(kSecondaryGroupName, 50);
407
408 // The trial should start inactive.
409 EXPECT_FALSE(FieldTrialList::IsTrialActive(kTrialName));
410
411 // Calling |GetGroupNameWithoutActivation()| should not activate the trial.
412 std::string group_name = trial->GetGroupNameWithoutActivation();
413 EXPECT_FALSE(group_name.empty());
414 EXPECT_FALSE(FieldTrialList::IsTrialActive(kTrialName));
415
416 // Calling |group_name()| should activate it and return the same group name.
417 EXPECT_EQ(group_name, trial->group_name());
418 EXPECT_TRUE(FieldTrialList::IsTrialActive(kTrialName));
419 }
420
TEST_F(FieldTrialTest,Save)421 TEST_F(FieldTrialTest, Save) {
422 std::string save_string;
423
424 scoped_refptr<FieldTrial> trial =
425 CreateFieldTrial("Some name", 10, "Default some name", nullptr);
426 // There is no winner yet, so no textual group name is associated with trial.
427 // In this case, the trial should not be included.
428 EXPECT_EQ("", trial->group_name_internal());
429 FieldTrialList::StatesToString(&save_string);
430 EXPECT_EQ("", save_string);
431 save_string.clear();
432
433 // Create a winning group.
434 trial->AppendGroup("Winner", 10);
435 // Finalize the group selection by accessing the selected group.
436 trial->group();
437 FieldTrialList::StatesToString(&save_string);
438 EXPECT_EQ("Some name/Winner/", save_string);
439 save_string.clear();
440
441 // Create a second trial and winning group.
442 scoped_refptr<FieldTrial> trial2 =
443 CreateFieldTrial("xxx", 10, "Default xxx", nullptr);
444 trial2->AppendGroup("yyyy", 10);
445 // Finalize the group selection by accessing the selected group.
446 trial2->group();
447
448 FieldTrialList::StatesToString(&save_string);
449 // We assume names are alphabetized... though this is not critical.
450 EXPECT_EQ("Some name/Winner/xxx/yyyy/", save_string);
451 save_string.clear();
452
453 // Create a third trial with only the default group.
454 scoped_refptr<FieldTrial> trial3 =
455 CreateFieldTrial("zzz", 10, "default", nullptr);
456 // Finalize the group selection by accessing the selected group.
457 trial3->group();
458
459 FieldTrialList::StatesToString(&save_string);
460 EXPECT_EQ("Some name/Winner/xxx/yyyy/zzz/default/", save_string);
461 }
462
TEST_F(FieldTrialTest,SaveAll)463 TEST_F(FieldTrialTest, SaveAll) {
464 std::string save_string;
465
466 scoped_refptr<FieldTrial> trial =
467 CreateFieldTrial("Some name", 10, "Default some name", nullptr);
468 EXPECT_EQ("", trial->group_name_internal());
469 FieldTrialList::AllStatesToString(&save_string, false);
470 EXPECT_EQ("Some name/Default some name/", save_string);
471 // Getting all states should have finalized the trial.
472 EXPECT_EQ("Default some name", trial->group_name_internal());
473 save_string.clear();
474
475 // Create a winning group.
476 trial = CreateFieldTrial("trial2", 10, "Default some name", nullptr);
477 trial->AppendGroup("Winner", 10);
478 // Finalize the group selection by accessing the selected group.
479 trial->group();
480 FieldTrialList::AllStatesToString(&save_string, false);
481 EXPECT_EQ("Some name/Default some name/*trial2/Winner/", save_string);
482 save_string.clear();
483
484 // Create a second trial and winning group.
485 scoped_refptr<FieldTrial> trial2 =
486 CreateFieldTrial("xxx", 10, "Default xxx", nullptr);
487 trial2->AppendGroup("yyyy", 10);
488 // Finalize the group selection by accessing the selected group.
489 trial2->group();
490
491 FieldTrialList::AllStatesToString(&save_string, false);
492 // We assume names are alphabetized... though this is not critical.
493 EXPECT_EQ("Some name/Default some name/*trial2/Winner/*xxx/yyyy/",
494 save_string);
495 save_string.clear();
496
497 // Create a third trial with only the default group.
498 scoped_refptr<FieldTrial> trial3 =
499 CreateFieldTrial("zzz", 10, "default", nullptr);
500
501 FieldTrialList::AllStatesToString(&save_string, false);
502 EXPECT_EQ("Some name/Default some name/*trial2/Winner/*xxx/yyyy/zzz/default/",
503 save_string);
504
505 // Create disabled study.
506 int default_group_number = -1;
507 scoped_refptr<FieldTrial> disabled_trial =
508 FieldTrialList::FactoryGetFieldTrial(
509 "Disabled trial name", 1000000000, "Default group",
510 FieldTrial::SESSION_RANDOMIZED, &default_group_number);
511 disabled_trial->AppendGroup("Disabled trial group name", 999999999);
512 disabled_trial->Disable();
513
514 save_string.clear();
515 FieldTrialList::AllStatesToString(&save_string, false);
516 EXPECT_EQ("Some name/Default some name/*trial2/Winner/*xxx/yyyy/zzz/default/",
517 save_string);
518 save_string.clear();
519 FieldTrialList::AllStatesToString(&save_string, true);
520 EXPECT_EQ(
521 "Disabled trial name/Default group/"
522 "Some name/Default some name/*trial2/Winner/*xxx/yyyy/zzz/default/",
523 save_string);
524 }
525
TEST_F(FieldTrialTest,Restore)526 TEST_F(FieldTrialTest, Restore) {
527 ASSERT_FALSE(FieldTrialList::TrialExists("Some_name"));
528 ASSERT_FALSE(FieldTrialList::TrialExists("xxx"));
529
530 FieldTrialList::CreateTrialsFromString("Some_name/Winner/xxx/yyyy/");
531
532 FieldTrial* trial = FieldTrialList::Find("Some_name");
533 ASSERT_NE(static_cast<FieldTrial*>(nullptr), trial);
534 EXPECT_EQ("Winner", trial->group_name());
535 EXPECT_EQ("Some_name", trial->trial_name());
536
537 trial = FieldTrialList::Find("xxx");
538 ASSERT_NE(static_cast<FieldTrial*>(nullptr), trial);
539 EXPECT_EQ("yyyy", trial->group_name());
540 EXPECT_EQ("xxx", trial->trial_name());
541 }
542
TEST_F(FieldTrialTest,RestoreNotEndingWithSlash)543 TEST_F(FieldTrialTest, RestoreNotEndingWithSlash) {
544 EXPECT_TRUE(FieldTrialList::CreateTrialsFromString("tname/gname"));
545
546 FieldTrial* trial = FieldTrialList::Find("tname");
547 ASSERT_NE(static_cast<FieldTrial*>(nullptr), trial);
548 EXPECT_EQ("gname", trial->group_name());
549 EXPECT_EQ("tname", trial->trial_name());
550 }
551
TEST_F(FieldTrialTest,BogusRestore)552 TEST_F(FieldTrialTest, BogusRestore) {
553 EXPECT_FALSE(FieldTrialList::CreateTrialsFromString("MissingSlash"));
554 EXPECT_FALSE(FieldTrialList::CreateTrialsFromString("MissingGroupName/"));
555 EXPECT_FALSE(FieldTrialList::CreateTrialsFromString("noname, only group/"));
556 EXPECT_FALSE(FieldTrialList::CreateTrialsFromString("/emptyname"));
557 EXPECT_FALSE(FieldTrialList::CreateTrialsFromString("*/emptyname"));
558 }
559
TEST_F(FieldTrialTest,DuplicateRestore)560 TEST_F(FieldTrialTest, DuplicateRestore) {
561 scoped_refptr<FieldTrial> trial =
562 CreateFieldTrial("Some name", 10, "Default", nullptr);
563 trial->AppendGroup("Winner", 10);
564 // Finalize the group selection by accessing the selected group.
565 trial->group();
566 std::string save_string;
567 FieldTrialList::StatesToString(&save_string);
568 EXPECT_EQ("Some name/Winner/", save_string);
569
570 // It is OK if we redundantly specify a winner.
571 EXPECT_TRUE(FieldTrialList::CreateTrialsFromString(save_string));
572
573 // But it is an error to try to change to a different winner.
574 EXPECT_FALSE(FieldTrialList::CreateTrialsFromString("Some name/Loser/"));
575 }
576
TEST_F(FieldTrialTest,CreateTrialsFromStringNotActive)577 TEST_F(FieldTrialTest, CreateTrialsFromStringNotActive) {
578 ASSERT_FALSE(FieldTrialList::TrialExists("Abc"));
579 ASSERT_FALSE(FieldTrialList::TrialExists("Xyz"));
580 ASSERT_TRUE(FieldTrialList::CreateTrialsFromString("Abc/def/Xyz/zyx/"));
581
582 FieldTrial::ActiveGroups active_groups;
583 FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
584 ASSERT_TRUE(active_groups.empty());
585
586 // Check that the values still get returned and querying them activates them.
587 EXPECT_EQ("def", FieldTrialList::FindFullName("Abc"));
588 EXPECT_EQ("zyx", FieldTrialList::FindFullName("Xyz"));
589
590 FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
591 ASSERT_EQ(2U, active_groups.size());
592 EXPECT_EQ("Abc", active_groups[0].trial_name);
593 EXPECT_EQ("def", active_groups[0].group_name);
594 EXPECT_EQ("Xyz", active_groups[1].trial_name);
595 EXPECT_EQ("zyx", active_groups[1].group_name);
596 }
597
TEST_F(FieldTrialTest,CreateTrialsFromStringForceActivation)598 TEST_F(FieldTrialTest, CreateTrialsFromStringForceActivation) {
599 ASSERT_FALSE(FieldTrialList::TrialExists("Abc"));
600 ASSERT_FALSE(FieldTrialList::TrialExists("def"));
601 ASSERT_FALSE(FieldTrialList::TrialExists("Xyz"));
602 ASSERT_TRUE(
603 FieldTrialList::CreateTrialsFromString("*Abc/cba/def/fed/*Xyz/zyx/"));
604
605 FieldTrial::ActiveGroups active_groups;
606 FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
607 ASSERT_EQ(2U, active_groups.size());
608 EXPECT_EQ("Abc", active_groups[0].trial_name);
609 EXPECT_EQ("cba", active_groups[0].group_name);
610 EXPECT_EQ("Xyz", active_groups[1].trial_name);
611 EXPECT_EQ("zyx", active_groups[1].group_name);
612 }
613
TEST_F(FieldTrialTest,CreateTrialsFromStringNotActiveObserver)614 TEST_F(FieldTrialTest, CreateTrialsFromStringNotActiveObserver) {
615 ASSERT_FALSE(FieldTrialList::TrialExists("Abc"));
616
617 TestFieldTrialObserver observer(TestFieldTrialObserver::ASYNCHRONOUS);
618 ASSERT_TRUE(FieldTrialList::CreateTrialsFromString("Abc/def/"));
619 RunLoop().RunUntilIdle();
620 // Observer shouldn't be notified.
621 EXPECT_TRUE(observer.trial_name().empty());
622
623 // Check that the values still get returned and querying them activates them.
624 EXPECT_EQ("def", FieldTrialList::FindFullName("Abc"));
625
626 RunLoop().RunUntilIdle();
627 EXPECT_EQ("Abc", observer.trial_name());
628 EXPECT_EQ("def", observer.group_name());
629 }
630
TEST_F(FieldTrialTest,CreateFieldTrial)631 TEST_F(FieldTrialTest, CreateFieldTrial) {
632 ASSERT_FALSE(FieldTrialList::TrialExists("Some_name"));
633
634 FieldTrialList::CreateFieldTrial("Some_name", "Winner");
635
636 FieldTrial* trial = FieldTrialList::Find("Some_name");
637 ASSERT_NE(static_cast<FieldTrial*>(nullptr), trial);
638 EXPECT_EQ("Winner", trial->group_name());
639 EXPECT_EQ("Some_name", trial->trial_name());
640 }
641
TEST_F(FieldTrialTest,CreateFieldTrialIsNotActive)642 TEST_F(FieldTrialTest, CreateFieldTrialIsNotActive) {
643 const char kTrialName[] = "CreateFieldTrialIsActiveTrial";
644 const char kWinnerGroup[] = "Winner";
645 ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
646 FieldTrialList::CreateFieldTrial(kTrialName, kWinnerGroup);
647
648 FieldTrial::ActiveGroups active_groups;
649 FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
650 EXPECT_TRUE(active_groups.empty());
651 }
652
TEST_F(FieldTrialTest,DuplicateFieldTrial)653 TEST_F(FieldTrialTest, DuplicateFieldTrial) {
654 scoped_refptr<FieldTrial> trial =
655 CreateFieldTrial("Some_name", 10, "Default", nullptr);
656 trial->AppendGroup("Winner", 10);
657
658 // It is OK if we redundantly specify a winner.
659 FieldTrial* trial1 = FieldTrialList::CreateFieldTrial("Some_name", "Winner");
660 EXPECT_TRUE(trial1 != nullptr);
661
662 // But it is an error to try to change to a different winner.
663 FieldTrial* trial2 = FieldTrialList::CreateFieldTrial("Some_name", "Loser");
664 EXPECT_TRUE(trial2 == nullptr);
665 }
666
TEST_F(FieldTrialTest,DisableImmediately)667 TEST_F(FieldTrialTest, DisableImmediately) {
668 int default_group_number = -1;
669 scoped_refptr<FieldTrial> trial =
670 CreateFieldTrial("trial", 100, "default", &default_group_number);
671 trial->Disable();
672 ASSERT_EQ("default", trial->group_name());
673 ASSERT_EQ(default_group_number, trial->group());
674 }
675
TEST_F(FieldTrialTest,DisableAfterInitialization)676 TEST_F(FieldTrialTest, DisableAfterInitialization) {
677 scoped_refptr<FieldTrial> trial =
678 CreateFieldTrial("trial", 100, "default", nullptr);
679 trial->AppendGroup("non_default", 100);
680 trial->Disable();
681 ASSERT_EQ("default", trial->group_name());
682 }
683
TEST_F(FieldTrialTest,ForcedFieldTrials)684 TEST_F(FieldTrialTest, ForcedFieldTrials) {
685 // Validate we keep the forced choice.
686 FieldTrial* forced_trial = FieldTrialList::CreateFieldTrial("Use the",
687 "Force");
688 EXPECT_STREQ("Force", forced_trial->group_name().c_str());
689
690 int default_group_number = -1;
691 scoped_refptr<FieldTrial> factory_trial =
692 CreateFieldTrial("Use the", 1000, "default", &default_group_number);
693 EXPECT_EQ(factory_trial.get(), forced_trial);
694
695 int chosen_group = factory_trial->AppendGroup("Force", 100);
696 EXPECT_EQ(chosen_group, factory_trial->group());
697 int not_chosen_group = factory_trial->AppendGroup("Dark Side", 100);
698 EXPECT_NE(chosen_group, not_chosen_group);
699
700 // Since we didn't force the default group, we should not be returned the
701 // chosen group as the default group.
702 EXPECT_NE(default_group_number, chosen_group);
703 int new_group = factory_trial->AppendGroup("Duck Tape", 800);
704 EXPECT_NE(chosen_group, new_group);
705 // The new group should not be the default group either.
706 EXPECT_NE(default_group_number, new_group);
707 }
708
TEST_F(FieldTrialTest,ForcedFieldTrialsDefaultGroup)709 TEST_F(FieldTrialTest, ForcedFieldTrialsDefaultGroup) {
710 // Forcing the default should use the proper group ID.
711 FieldTrial* forced_trial = FieldTrialList::CreateFieldTrial("Trial Name",
712 "Default");
713 int default_group_number = -1;
714 scoped_refptr<FieldTrial> factory_trial =
715 CreateFieldTrial("Trial Name", 1000, "Default", &default_group_number);
716 EXPECT_EQ(forced_trial, factory_trial.get());
717
718 int other_group = factory_trial->AppendGroup("Not Default", 100);
719 EXPECT_STREQ("Default", factory_trial->group_name().c_str());
720 EXPECT_EQ(default_group_number, factory_trial->group());
721 EXPECT_NE(other_group, factory_trial->group());
722
723 int new_other_group = factory_trial->AppendGroup("Not Default Either", 800);
724 EXPECT_NE(new_other_group, factory_trial->group());
725 }
726
TEST_F(FieldTrialTest,SetForced)727 TEST_F(FieldTrialTest, SetForced) {
728 // Start by setting a trial for which we ensure a winner...
729 int default_group_number = -1;
730 scoped_refptr<FieldTrial> forced_trial =
731 CreateFieldTrial("Use the", 1, "default", &default_group_number);
732 EXPECT_EQ(forced_trial, forced_trial);
733
734 int forced_group = forced_trial->AppendGroup("Force", 1);
735 EXPECT_EQ(forced_group, forced_trial->group());
736
737 // Now force it.
738 forced_trial->SetForced();
739
740 // Now try to set it up differently as a hard coded registration would.
741 scoped_refptr<FieldTrial> hard_coded_trial =
742 CreateFieldTrial("Use the", 1, "default", &default_group_number);
743 EXPECT_EQ(hard_coded_trial, forced_trial);
744
745 int would_lose_group = hard_coded_trial->AppendGroup("Force", 0);
746 EXPECT_EQ(forced_group, hard_coded_trial->group());
747 EXPECT_EQ(forced_group, would_lose_group);
748
749 // Same thing if we would have done it to win again.
750 scoped_refptr<FieldTrial> other_hard_coded_trial =
751 CreateFieldTrial("Use the", 1, "default", &default_group_number);
752 EXPECT_EQ(other_hard_coded_trial, forced_trial);
753
754 int would_win_group = other_hard_coded_trial->AppendGroup("Force", 1);
755 EXPECT_EQ(forced_group, other_hard_coded_trial->group());
756 EXPECT_EQ(forced_group, would_win_group);
757 }
758
TEST_F(FieldTrialTest,SetForcedDefaultOnly)759 TEST_F(FieldTrialTest, SetForcedDefaultOnly) {
760 const char kTrialName[] = "SetForcedDefaultOnly";
761 ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
762
763 int default_group = -1;
764 scoped_refptr<FieldTrial> trial =
765 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
766 trial->SetForced();
767
768 trial = CreateFieldTrial(kTrialName, 100, kDefaultGroupName, nullptr);
769 EXPECT_EQ(default_group, trial->group());
770 EXPECT_EQ(kDefaultGroupName, trial->group_name());
771 }
772
TEST_F(FieldTrialTest,SetForcedDefaultWithExtraGroup)773 TEST_F(FieldTrialTest, SetForcedDefaultWithExtraGroup) {
774 const char kTrialName[] = "SetForcedDefaultWithExtraGroup";
775 ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
776
777 int default_group = -1;
778 scoped_refptr<FieldTrial> trial =
779 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
780 trial->SetForced();
781
782 trial = CreateFieldTrial(kTrialName, 100, kDefaultGroupName, nullptr);
783 const int extra_group = trial->AppendGroup("Extra", 100);
784 EXPECT_EQ(default_group, trial->group());
785 EXPECT_NE(extra_group, trial->group());
786 EXPECT_EQ(kDefaultGroupName, trial->group_name());
787 }
788
TEST_F(FieldTrialTest,SetForcedTurnFeatureOn)789 TEST_F(FieldTrialTest, SetForcedTurnFeatureOn) {
790 const char kTrialName[] = "SetForcedTurnFeatureOn";
791 const char kExtraGroupName[] = "Extra";
792 ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
793
794 // Simulate a server-side (forced) config that turns the feature on when the
795 // original hard-coded config had it disabled.
796 scoped_refptr<FieldTrial> forced_trial =
797 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, nullptr);
798 forced_trial->AppendGroup(kExtraGroupName, 100);
799 forced_trial->SetForced();
800
801 int default_group = -1;
802 scoped_refptr<FieldTrial> client_trial =
803 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
804 const int extra_group = client_trial->AppendGroup(kExtraGroupName, 0);
805 EXPECT_NE(default_group, extra_group);
806
807 EXPECT_FALSE(client_trial->group_reported_);
808 EXPECT_EQ(extra_group, client_trial->group());
809 EXPECT_TRUE(client_trial->group_reported_);
810 EXPECT_EQ(kExtraGroupName, client_trial->group_name());
811 }
812
TEST_F(FieldTrialTest,SetForcedTurnFeatureOff)813 TEST_F(FieldTrialTest, SetForcedTurnFeatureOff) {
814 const char kTrialName[] = "SetForcedTurnFeatureOff";
815 const char kExtraGroupName[] = "Extra";
816 ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
817
818 // Simulate a server-side (forced) config that turns the feature off when the
819 // original hard-coded config had it enabled.
820 scoped_refptr<FieldTrial> forced_trial =
821 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, nullptr);
822 forced_trial->AppendGroup(kExtraGroupName, 0);
823 forced_trial->SetForced();
824
825 int default_group = -1;
826 scoped_refptr<FieldTrial> client_trial =
827 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
828 const int extra_group = client_trial->AppendGroup(kExtraGroupName, 100);
829 EXPECT_NE(default_group, extra_group);
830
831 EXPECT_FALSE(client_trial->group_reported_);
832 EXPECT_EQ(default_group, client_trial->group());
833 EXPECT_TRUE(client_trial->group_reported_);
834 EXPECT_EQ(kDefaultGroupName, client_trial->group_name());
835 }
836
TEST_F(FieldTrialTest,SetForcedChangeDefault_Default)837 TEST_F(FieldTrialTest, SetForcedChangeDefault_Default) {
838 const char kTrialName[] = "SetForcedDefaultGroupChange";
839 const char kGroupAName[] = "A";
840 const char kGroupBName[] = "B";
841 ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
842
843 // Simulate a server-side (forced) config that switches which group is default
844 // and ensures that the non-forced code receives the correct group numbers.
845 scoped_refptr<FieldTrial> forced_trial =
846 CreateFieldTrial(kTrialName, 100, kGroupAName, nullptr);
847 forced_trial->AppendGroup(kGroupBName, 100);
848 forced_trial->SetForced();
849
850 int default_group = -1;
851 scoped_refptr<FieldTrial> client_trial =
852 CreateFieldTrial(kTrialName, 100, kGroupBName, &default_group);
853 const int extra_group = client_trial->AppendGroup(kGroupAName, 50);
854 EXPECT_NE(default_group, extra_group);
855
856 EXPECT_FALSE(client_trial->group_reported_);
857 EXPECT_EQ(default_group, client_trial->group());
858 EXPECT_TRUE(client_trial->group_reported_);
859 EXPECT_EQ(kGroupBName, client_trial->group_name());
860 }
861
TEST_F(FieldTrialTest,SetForcedChangeDefault_NonDefault)862 TEST_F(FieldTrialTest, SetForcedChangeDefault_NonDefault) {
863 const char kTrialName[] = "SetForcedDefaultGroupChange";
864 const char kGroupAName[] = "A";
865 const char kGroupBName[] = "B";
866 ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
867
868 // Simulate a server-side (forced) config that switches which group is default
869 // and ensures that the non-forced code receives the correct group numbers.
870 scoped_refptr<FieldTrial> forced_trial =
871 CreateFieldTrial(kTrialName, 100, kGroupAName, nullptr);
872 forced_trial->AppendGroup(kGroupBName, 0);
873 forced_trial->SetForced();
874
875 int default_group = -1;
876 scoped_refptr<FieldTrial> client_trial =
877 CreateFieldTrial(kTrialName, 100, kGroupBName, &default_group);
878 const int extra_group = client_trial->AppendGroup(kGroupAName, 50);
879 EXPECT_NE(default_group, extra_group);
880
881 EXPECT_FALSE(client_trial->group_reported_);
882 EXPECT_EQ(extra_group, client_trial->group());
883 EXPECT_TRUE(client_trial->group_reported_);
884 EXPECT_EQ(kGroupAName, client_trial->group_name());
885 }
886
TEST_F(FieldTrialTest,Observe)887 TEST_F(FieldTrialTest, Observe) {
888 const char kTrialName[] = "TrialToObserve1";
889 const char kSecondaryGroupName[] = "SecondaryGroup";
890
891 TestFieldTrialObserver observer(TestFieldTrialObserver::ASYNCHRONOUS);
892 int default_group = -1;
893 scoped_refptr<FieldTrial> trial =
894 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
895 const int secondary_group = trial->AppendGroup(kSecondaryGroupName, 50);
896 const int chosen_group = trial->group();
897 EXPECT_TRUE(chosen_group == default_group || chosen_group == secondary_group);
898
899 EXPECT_EQ(kTrialName, observer.trial_name());
900 if (chosen_group == default_group)
901 EXPECT_EQ(kDefaultGroupName, observer.group_name());
902 else
903 EXPECT_EQ(kSecondaryGroupName, observer.group_name());
904 }
905
TEST_F(FieldTrialTest,SynchronousObserver)906 TEST_F(FieldTrialTest, SynchronousObserver) {
907 const char kTrialName[] = "TrialToObserve1";
908 const char kSecondaryGroupName[] = "SecondaryGroup";
909
910 TestFieldTrialObserver observer(TestFieldTrialObserver::SYNCHRONOUS);
911 int default_group = -1;
912 scoped_refptr<FieldTrial> trial =
913 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
914 const int secondary_group = trial->AppendGroup(kSecondaryGroupName, 50);
915 const int chosen_group = trial->group();
916 EXPECT_TRUE(chosen_group == default_group || chosen_group == secondary_group);
917
918 // The observer should be notified synchronously by the group() call.
919 EXPECT_EQ(kTrialName, observer.trial_name());
920 if (chosen_group == default_group)
921 EXPECT_EQ(kDefaultGroupName, observer.group_name());
922 else
923 EXPECT_EQ(kSecondaryGroupName, observer.group_name());
924 }
925
TEST_F(FieldTrialTest,ObserveDisabled)926 TEST_F(FieldTrialTest, ObserveDisabled) {
927 const char kTrialName[] = "TrialToObserve2";
928
929 TestFieldTrialObserver observer(TestFieldTrialObserver::ASYNCHRONOUS);
930 int default_group = -1;
931 scoped_refptr<FieldTrial> trial =
932 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
933 trial->AppendGroup("A", 25);
934 trial->AppendGroup("B", 25);
935 trial->AppendGroup("C", 25);
936 trial->Disable();
937
938 // Observer shouldn't be notified of a disabled trial.
939 RunLoop().RunUntilIdle();
940 EXPECT_TRUE(observer.trial_name().empty());
941 EXPECT_TRUE(observer.group_name().empty());
942
943 // Observer shouldn't be notified even after a |group()| call.
944 EXPECT_EQ(default_group, trial->group());
945 RunLoop().RunUntilIdle();
946 EXPECT_TRUE(observer.trial_name().empty());
947 EXPECT_TRUE(observer.group_name().empty());
948 }
949
TEST_F(FieldTrialTest,ObserveForcedDisabled)950 TEST_F(FieldTrialTest, ObserveForcedDisabled) {
951 const char kTrialName[] = "TrialToObserve3";
952
953 TestFieldTrialObserver observer(TestFieldTrialObserver::ASYNCHRONOUS);
954 int default_group = -1;
955 scoped_refptr<FieldTrial> trial =
956 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, &default_group);
957 trial->AppendGroup("A", 25);
958 trial->AppendGroup("B", 25);
959 trial->AppendGroup("C", 25);
960 trial->SetForced();
961 trial->Disable();
962
963 // Observer shouldn't be notified of a disabled trial, even when forced.
964 RunLoop().RunUntilIdle();
965 EXPECT_TRUE(observer.trial_name().empty());
966 EXPECT_TRUE(observer.group_name().empty());
967
968 // Observer shouldn't be notified even after a |group()| call.
969 EXPECT_EQ(default_group, trial->group());
970 RunLoop().RunUntilIdle();
971 EXPECT_TRUE(observer.trial_name().empty());
972 EXPECT_TRUE(observer.group_name().empty());
973 }
974
TEST_F(FieldTrialTest,DisabledTrialNotActive)975 TEST_F(FieldTrialTest, DisabledTrialNotActive) {
976 const char kTrialName[] = "DisabledTrial";
977 ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
978
979 scoped_refptr<FieldTrial> trial =
980 CreateFieldTrial(kTrialName, 100, kDefaultGroupName, nullptr);
981 trial->AppendGroup("X", 50);
982 trial->Disable();
983
984 // Ensure the trial is not listed as active.
985 FieldTrial::ActiveGroups active_groups;
986 FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
987 EXPECT_TRUE(active_groups.empty());
988
989 // Ensure the trial is not listed in the |StatesToString()| result.
990 std::string states;
991 FieldTrialList::StatesToString(&states);
992 EXPECT_TRUE(states.empty());
993 }
994
TEST_F(FieldTrialTest,NotDisabled)995 TEST_F(FieldTrialTest, NotDisabled) {
996 const char kTrialName[] = "NotDisabled";
997 const char kGroupName[] = "Group2";
998 const int kProbability = 100;
999 ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
1000
1001 scoped_refptr<FieldTrial> trial =
1002 CreateFieldTrial(kTrialName, kProbability, kDefaultGroupName, nullptr);
1003 trial->AppendGroup(kGroupName, kProbability);
1004 EXPECT_EQ(kGroupName, trial->group_name());
1005 }
1006
TEST_F(FieldTrialTest,FloatBoundariesGiveEqualGroupSizes)1007 TEST_F(FieldTrialTest, FloatBoundariesGiveEqualGroupSizes) {
1008 const int kBucketCount = 100;
1009
1010 // Try each boundary value |i / 100.0| as the entropy value.
1011 for (int i = 0; i < kBucketCount; ++i) {
1012 const double entropy = i / static_cast<double>(kBucketCount);
1013
1014 scoped_refptr<FieldTrial> trial(
1015 new FieldTrial("test", kBucketCount, "default", entropy));
1016 for (int j = 0; j < kBucketCount; ++j)
1017 trial->AppendGroup(NumberToString(j), 1);
1018
1019 EXPECT_EQ(NumberToString(i), trial->group_name());
1020 }
1021 }
1022
TEST_F(FieldTrialTest,DoesNotSurpassTotalProbability)1023 TEST_F(FieldTrialTest, DoesNotSurpassTotalProbability) {
1024 const double kEntropyValue = 1.0 - 1e-9;
1025 ASSERT_LT(kEntropyValue, 1.0);
1026
1027 scoped_refptr<FieldTrial> trial(
1028 new FieldTrial("test", 2, "default", kEntropyValue));
1029 trial->AppendGroup("1", 1);
1030 trial->AppendGroup("2", 1);
1031
1032 EXPECT_EQ("2", trial->group_name());
1033 }
1034
TEST_F(FieldTrialTest,CreateSimulatedFieldTrial)1035 TEST_F(FieldTrialTest, CreateSimulatedFieldTrial) {
1036 const char kTrialName[] = "CreateSimulatedFieldTrial";
1037 ASSERT_FALSE(FieldTrialList::TrialExists(kTrialName));
1038
1039 // Different cases to test, e.g. default vs. non default group being chosen.
1040 struct {
1041 double entropy_value;
1042 const char* expected_group;
1043 } test_cases[] = {
1044 { 0.4, "A" },
1045 { 0.85, "B" },
1046 { 0.95, kDefaultGroupName },
1047 };
1048
1049 for (size_t i = 0; i < base::size(test_cases); ++i) {
1050 TestFieldTrialObserver observer(TestFieldTrialObserver::ASYNCHRONOUS);
1051 scoped_refptr<FieldTrial> trial(
1052 FieldTrial::CreateSimulatedFieldTrial(kTrialName, 100, kDefaultGroupName,
1053 test_cases[i].entropy_value));
1054 trial->AppendGroup("A", 80);
1055 trial->AppendGroup("B", 10);
1056 EXPECT_EQ(test_cases[i].expected_group, trial->group_name());
1057
1058 // Field trial shouldn't have been registered with the list.
1059 EXPECT_FALSE(FieldTrialList::TrialExists(kTrialName));
1060 EXPECT_EQ(0u, FieldTrialList::GetFieldTrialCount());
1061
1062 // Observer shouldn't have been notified.
1063 RunLoop().RunUntilIdle();
1064 EXPECT_TRUE(observer.trial_name().empty());
1065
1066 // The trial shouldn't be in the active set of trials.
1067 FieldTrial::ActiveGroups active_groups;
1068 FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
1069 EXPECT_TRUE(active_groups.empty());
1070
1071 // The trial shouldn't be listed in the |StatesToString()| result.
1072 std::string states;
1073 FieldTrialList::StatesToString(&states);
1074 EXPECT_TRUE(states.empty());
1075 }
1076 }
1077
TEST(FieldTrialTestWithoutList,StatesStringFormat)1078 TEST(FieldTrialTestWithoutList, StatesStringFormat) {
1079 std::string save_string;
1080
1081 // The test suite instantiates a FieldTrialList but for the purpose of these
1082 // tests it's cleaner to start from scratch.
1083 test::ScopedFieldTrialListResetter trial_list_resetter_;
1084
1085 // Scoping the first FieldTrialList, as we need another one to test the
1086 // importing function.
1087 {
1088 FieldTrialList field_trial_list(nullptr);
1089 scoped_refptr<FieldTrial> trial =
1090 CreateFieldTrial("Abc", 10, "Default some name", nullptr);
1091 trial->AppendGroup("cba", 10);
1092 trial->group();
1093 scoped_refptr<FieldTrial> trial2 =
1094 CreateFieldTrial("Xyz", 10, "Default xxx", nullptr);
1095 trial2->AppendGroup("zyx", 10);
1096 trial2->group();
1097 scoped_refptr<FieldTrial> trial3 =
1098 CreateFieldTrial("zzz", 10, "default", nullptr);
1099
1100 FieldTrialList::AllStatesToString(&save_string, false);
1101 }
1102
1103 // Starting with a new blank FieldTrialList.
1104 FieldTrialList field_trial_list(nullptr);
1105 ASSERT_TRUE(field_trial_list.CreateTrialsFromString(save_string));
1106
1107 FieldTrial::ActiveGroups active_groups;
1108 field_trial_list.GetActiveFieldTrialGroups(&active_groups);
1109 ASSERT_EQ(2U, active_groups.size());
1110 EXPECT_EQ("Abc", active_groups[0].trial_name);
1111 EXPECT_EQ("cba", active_groups[0].group_name);
1112 EXPECT_EQ("Xyz", active_groups[1].trial_name);
1113 EXPECT_EQ("zyx", active_groups[1].group_name);
1114 EXPECT_TRUE(field_trial_list.TrialExists("zzz"));
1115 }
1116
TEST(FieldTrialDeathTest,OneTimeRandomizedTrialWithoutFieldTrialList)1117 TEST(FieldTrialDeathTest, OneTimeRandomizedTrialWithoutFieldTrialList) {
1118 test::ScopedFieldTrialListResetter resetter;
1119 // Trying to instantiate a one-time randomized field trial before the
1120 // FieldTrialList is created should crash.
1121 EXPECT_DEATH_IF_SUPPORTED(
1122 FieldTrialList::FactoryGetFieldTrial(
1123 "OneTimeRandomizedTrialWithoutFieldTrialList", 100, kDefaultGroupName,
1124 FieldTrial::ONE_TIME_RANDOMIZED, nullptr),
1125 "");
1126 }
1127
1128 class FieldTrialListTest : public ::testing::Test {
1129 public:
1130 FieldTrialListTest() = default;
1131
1132 private:
1133 // The test suite instantiates a FieldTrialList but for the purpose of these
1134 // tests it's cleaner to start from scratch.
1135 test::ScopedFieldTrialListResetter trial_list_resetter_;
1136 };
1137
1138 #if defined(OS_FUCHSIA)
1139 // TODO(crbug.com/752368): This is flaky on Fuchsia.
1140 #define MAYBE_TestCopyFieldTrialStateToFlags \
1141 DISABLED_TestCopyFieldTrialStateToFlags
1142 #else
1143 #define MAYBE_TestCopyFieldTrialStateToFlags TestCopyFieldTrialStateToFlags
1144 #endif
TEST_F(FieldTrialListTest,MAYBE_TestCopyFieldTrialStateToFlags)1145 TEST_F(FieldTrialListTest, MAYBE_TestCopyFieldTrialStateToFlags) {
1146 constexpr char kFieldTrialHandleSwitch[] = "test-field-trial-handle";
1147 constexpr char kEnableFeaturesSwitch[] = "test-enable-features";
1148 constexpr char kDisableFeaturesSwitch[] = "test-disable-features";
1149
1150 FieldTrialList field_trial_list(std::make_unique<MockEntropyProvider>());
1151
1152 std::unique_ptr<FeatureList> feature_list(new FeatureList);
1153 feature_list->InitializeFromCommandLine("A,B", "C");
1154
1155 FieldTrial* trial = FieldTrialList::CreateFieldTrial("Trial1", "Group1");
1156 feature_list->RegisterFieldTrialOverride(
1157 "MyFeature", FeatureList::OVERRIDE_ENABLE_FEATURE, trial);
1158
1159 test::ScopedFeatureList scoped_feature_list;
1160 scoped_feature_list.InitWithFeatureList(std::move(feature_list));
1161
1162 FilePath test_file_path = FilePath(FILE_PATH_LITERAL("Program"));
1163 CommandLine command_line = CommandLine(test_file_path);
1164
1165 FieldTrialList::CopyFieldTrialStateToFlags(
1166 kFieldTrialHandleSwitch, kEnableFeaturesSwitch, kDisableFeaturesSwitch,
1167 &command_line);
1168 EXPECT_TRUE(command_line.HasSwitch(kFieldTrialHandleSwitch));
1169
1170 // Explictly specified enabled/disabled features should be specified.
1171 EXPECT_EQ("A,B", command_line.GetSwitchValueASCII(kEnableFeaturesSwitch));
1172 EXPECT_EQ("C", command_line.GetSwitchValueASCII(kDisableFeaturesSwitch));
1173 }
1174
TEST_F(FieldTrialListTest,InstantiateAllocator)1175 TEST_F(FieldTrialListTest, InstantiateAllocator) {
1176 FieldTrialList field_trial_list(nullptr);
1177
1178 FieldTrialList::CreateFieldTrial("Trial1", "Group1");
1179
1180 FieldTrialList::InstantiateFieldTrialAllocatorIfNeeded();
1181 const void* memory = field_trial_list.field_trial_allocator_->data();
1182 size_t used = field_trial_list.field_trial_allocator_->used();
1183
1184 // Ensure that the function is idempotent.
1185 FieldTrialList::InstantiateFieldTrialAllocatorIfNeeded();
1186 const void* new_memory = field_trial_list.field_trial_allocator_->data();
1187 size_t new_used = field_trial_list.field_trial_allocator_->used();
1188 EXPECT_EQ(memory, new_memory);
1189 EXPECT_EQ(used, new_used);
1190 }
1191
TEST_F(FieldTrialListTest,AddTrialsToAllocator)1192 TEST_F(FieldTrialListTest, AddTrialsToAllocator) {
1193 std::string save_string;
1194 base::ReadOnlySharedMemoryRegion shm_region;
1195
1196 // Scoping the first FieldTrialList, as we need another one to test that it
1197 // matches.
1198 {
1199 FieldTrialList field_trial_list1(nullptr);
1200 FieldTrialList::CreateFieldTrial("Trial1", "Group1");
1201 FieldTrialList::InstantiateFieldTrialAllocatorIfNeeded();
1202 FieldTrialList::AllStatesToString(&save_string, false);
1203 shm_region = FieldTrialList::DuplicateFieldTrialSharedMemoryForTesting();
1204 ASSERT_TRUE(shm_region.IsValid());
1205 }
1206
1207 FieldTrialList field_trial_list2(nullptr);
1208 // 4 KiB is enough to hold the trials only created for this test.
1209 base::ReadOnlySharedMemoryMapping shm_mapping = shm_region.MapAt(0, 4 << 10);
1210 ASSERT_TRUE(shm_mapping.IsValid());
1211 FieldTrialList::CreateTrialsFromSharedMemoryMapping(std::move(shm_mapping));
1212 std::string check_string;
1213 FieldTrialList::AllStatesToString(&check_string, false);
1214 EXPECT_EQ(save_string, check_string);
1215 }
1216
TEST_F(FieldTrialListTest,DoNotAddSimulatedFieldTrialsToAllocator)1217 TEST_F(FieldTrialListTest, DoNotAddSimulatedFieldTrialsToAllocator) {
1218 constexpr char kTrialName[] = "trial";
1219 base::ReadOnlySharedMemoryRegion shm_region;
1220 {
1221 FieldTrialList field_trial_list1(nullptr);
1222
1223 // Create a simulated trial and a real trial and call group() on them, which
1224 // should only add the real trial to the field trial allocator.
1225 FieldTrialList::InstantiateFieldTrialAllocatorIfNeeded();
1226
1227 // This shouldn't add to the allocator.
1228 scoped_refptr<FieldTrial> simulated_trial =
1229 FieldTrial::CreateSimulatedFieldTrial(kTrialName, 100, "Simulated",
1230 0.95);
1231 simulated_trial->group();
1232
1233 // This should add to the allocator.
1234 FieldTrial* real_trial =
1235 FieldTrialList::CreateFieldTrial(kTrialName, "Real");
1236 real_trial->group();
1237
1238 shm_region = FieldTrialList::DuplicateFieldTrialSharedMemoryForTesting();
1239 ASSERT_TRUE(shm_region.IsValid());
1240 }
1241
1242 // Check that there's only one entry in the allocator.
1243 FieldTrialList field_trial_list2(nullptr);
1244 // 4 KiB is enough to hold the trials only created for this test.
1245 base::ReadOnlySharedMemoryMapping shm_mapping = shm_region.MapAt(0, 4 << 10);
1246 ASSERT_TRUE(shm_mapping.IsValid());
1247 FieldTrialList::CreateTrialsFromSharedMemoryMapping(std::move(shm_mapping));
1248 std::string check_string;
1249 FieldTrialList::AllStatesToString(&check_string, false);
1250 ASSERT_EQ(check_string.find("Simulated"), std::string::npos);
1251 }
1252
TEST_F(FieldTrialListTest,AssociateFieldTrialParams)1253 TEST_F(FieldTrialListTest, AssociateFieldTrialParams) {
1254 FieldTrialList field_trial_list(nullptr);
1255
1256 std::string trial_name("Trial1");
1257 std::string group_name("Group1");
1258
1259 // Create a field trial with some params.
1260 FieldTrialList::CreateFieldTrial(trial_name, group_name);
1261 std::map<std::string, std::string> params;
1262 params["key1"] = "value1";
1263 params["key2"] = "value2";
1264 FieldTrialParamAssociator::GetInstance()->AssociateFieldTrialParams(
1265 trial_name, group_name, params);
1266 FieldTrialList::InstantiateFieldTrialAllocatorIfNeeded();
1267
1268 // Clear all cached params from the associator.
1269 FieldTrialParamAssociator::GetInstance()->ClearAllCachedParamsForTesting();
1270 // Check that the params have been cleared from the cache.
1271 std::map<std::string, std::string> cached_params;
1272 FieldTrialParamAssociator::GetInstance()->GetFieldTrialParamsWithoutFallback(
1273 trial_name, group_name, &cached_params);
1274 EXPECT_EQ(0U, cached_params.size());
1275
1276 // Check that we fetch the param from shared memory properly.
1277 std::map<std::string, std::string> new_params;
1278 FieldTrialParamAssociator::GetInstance()->GetFieldTrialParams(trial_name,
1279 &new_params);
1280 EXPECT_EQ("value1", new_params["key1"]);
1281 EXPECT_EQ("value2", new_params["key2"]);
1282 EXPECT_EQ(2U, new_params.size());
1283 }
1284
1285 #if defined(OS_FUCHSIA)
1286 // TODO(crbug.com/752368): This is flaky on Fuchsia.
1287 #define MAYBE_ClearParamsFromSharedMemory DISABLED_ClearParamsFromSharedMemory
1288 #else
1289 #define MAYBE_ClearParamsFromSharedMemory ClearParamsFromSharedMemory
1290 #endif
TEST_F(FieldTrialListTest,MAYBE_ClearParamsFromSharedMemory)1291 TEST_F(FieldTrialListTest, MAYBE_ClearParamsFromSharedMemory) {
1292 std::string trial_name("Trial1");
1293 std::string group_name("Group1");
1294
1295 base::ReadOnlySharedMemoryRegion shm_region;
1296 {
1297 FieldTrialList field_trial_list1(nullptr);
1298
1299 // Create a field trial with some params.
1300 FieldTrial* trial =
1301 FieldTrialList::CreateFieldTrial(trial_name, group_name);
1302 std::map<std::string, std::string> params;
1303 params["key1"] = "value1";
1304 params["key2"] = "value2";
1305 FieldTrialParamAssociator::GetInstance()->AssociateFieldTrialParams(
1306 trial_name, group_name, params);
1307 FieldTrialList::InstantiateFieldTrialAllocatorIfNeeded();
1308
1309 // Clear all params from the associator AND shared memory. The allocated
1310 // segments should be different.
1311 FieldTrial::FieldTrialRef old_ref = trial->ref_;
1312 FieldTrialParamAssociator::GetInstance()->ClearAllParamsForTesting();
1313 FieldTrial::FieldTrialRef new_ref = trial->ref_;
1314 EXPECT_NE(old_ref, new_ref);
1315
1316 // Check that there are no params associated with the field trial anymore.
1317 std::map<std::string, std::string> new_params;
1318 FieldTrialParamAssociator::GetInstance()->GetFieldTrialParams(trial_name,
1319 &new_params);
1320 EXPECT_EQ(0U, new_params.size());
1321
1322 // Now duplicate the handle so we can easily check that the trial is still
1323 // in shared memory via AllStatesToString.
1324 shm_region = FieldTrialList::DuplicateFieldTrialSharedMemoryForTesting();
1325 ASSERT_TRUE(shm_region.IsValid());
1326 }
1327
1328 // Check that we have the trial.
1329 FieldTrialList field_trial_list2(nullptr);
1330 // 4 KiB is enough to hold the trials only created for this test.
1331 base::ReadOnlySharedMemoryMapping shm_mapping = shm_region.MapAt(0, 4 << 10);
1332 ASSERT_TRUE(shm_mapping.IsValid());
1333 FieldTrialList::CreateTrialsFromSharedMemoryMapping(std::move(shm_mapping));
1334 std::string check_string;
1335 FieldTrialList::AllStatesToString(&check_string, false);
1336 EXPECT_EQ("*Trial1/Group1/", check_string);
1337 }
1338
TEST_F(FieldTrialListTest,DumpAndFetchFromSharedMemory)1339 TEST_F(FieldTrialListTest, DumpAndFetchFromSharedMemory) {
1340 std::string trial_name("Trial1");
1341 std::string group_name("Group1");
1342
1343 // Create a field trial with some params.
1344 FieldTrialList field_trial_list(nullptr);
1345 FieldTrialList::CreateFieldTrial(trial_name, group_name);
1346 std::map<std::string, std::string> params;
1347 params["key1"] = "value1";
1348 params["key2"] = "value2";
1349 FieldTrialParamAssociator::GetInstance()->AssociateFieldTrialParams(
1350 trial_name, group_name, params);
1351
1352 // 4 KiB is enough to hold the trials only created for this test.
1353 base::MappedReadOnlyRegion shm =
1354 base::ReadOnlySharedMemoryRegion::Create(4 << 10);
1355 ASSERT_TRUE(shm.IsValid());
1356 // We _could_ use PersistentMemoryAllocator, this just has less params.
1357 WritableSharedPersistentMemoryAllocator allocator(std::move(shm.mapping), 1,
1358 "");
1359
1360 // Dump and subsequently retrieve the field trial to |allocator|.
1361 FieldTrialList::DumpAllFieldTrialsToPersistentAllocator(&allocator);
1362 std::vector<const FieldTrial::FieldTrialEntry*> entries =
1363 FieldTrialList::GetAllFieldTrialsFromPersistentAllocator(allocator);
1364
1365 // Check that we have the entry we put in.
1366 EXPECT_EQ(1u, entries.size());
1367 const FieldTrial::FieldTrialEntry* entry = entries[0];
1368
1369 // Check that the trial and group names match.
1370 StringPiece shm_trial_name;
1371 StringPiece shm_group_name;
1372 entry->GetTrialAndGroupName(&shm_trial_name, &shm_group_name);
1373 EXPECT_EQ(trial_name, shm_trial_name);
1374 EXPECT_EQ(group_name, shm_group_name);
1375
1376 // Check that the params match.
1377 std::map<std::string, std::string> shm_params;
1378 entry->GetParams(&shm_params);
1379 EXPECT_EQ(2u, shm_params.size());
1380 EXPECT_EQ("value1", shm_params["key1"]);
1381 EXPECT_EQ("value2", shm_params["key2"]);
1382 }
1383
1384 // Shared-memory distribution of FieldTrial to child process is not implemented
1385 // on Fuchsia: http://crbug.com/752368.
1386 #if !defined(OS_NACL) && !defined(OS_IOS) && !defined(OS_FUCHSIA)
MULTIPROCESS_TEST_MAIN(SerializeSharedMemoryRegionMetadata)1387 MULTIPROCESS_TEST_MAIN(SerializeSharedMemoryRegionMetadata) {
1388 std::string serialized =
1389 CommandLine::ForCurrentProcess()->GetSwitchValueASCII("field_trials");
1390 std::string guid_string =
1391 CommandLine::ForCurrentProcess()->GetSwitchValueASCII("guid");
1392
1393 #if defined(OS_WIN) || defined(OS_MAC)
1394 base::ReadOnlySharedMemoryRegion deserialized =
1395 FieldTrialList::DeserializeSharedMemoryRegionMetadata(serialized);
1396 #elif defined(OS_ANDROID)
1397 // Use the arbitrary fd value selected in the main process.
1398 // File descriptors are not remapped on Android. They have to be looked up in
1399 // the GlobalDescriptors table instead.
1400 int fd = base::GlobalDescriptors::GetInstance()->MaybeGet(42);
1401 CHECK_NE(fd, -1);
1402 base::ReadOnlySharedMemoryRegion deserialized =
1403 FieldTrialList::DeserializeSharedMemoryRegionMetadata(fd, serialized);
1404 #else
1405 // Use the arbitrary fd value selected in the main process.
1406 base::ReadOnlySharedMemoryRegion deserialized =
1407 FieldTrialList::DeserializeSharedMemoryRegionMetadata(42, serialized);
1408 #endif // defined(OS_WIN) || defined(OS_MAC)
1409 CHECK(deserialized.IsValid());
1410 CHECK_EQ(deserialized.GetGUID().ToString(), guid_string);
1411 CHECK(!deserialized.GetGUID().is_empty());
1412
1413 return 0;
1414 }
1415
TEST_F(FieldTrialListTest,SerializeSharedMemoryRegionMetadata)1416 TEST_F(FieldTrialListTest, SerializeSharedMemoryRegionMetadata) {
1417 base::MappedReadOnlyRegion shm =
1418 base::ReadOnlySharedMemoryRegion::Create(4 << 10);
1419 ASSERT_TRUE(shm.IsValid());
1420
1421 std::string serialized =
1422 FieldTrialList::SerializeSharedMemoryRegionMetadata(shm.region);
1423
1424 LaunchOptions options;
1425
1426 #if defined(OS_WIN)
1427 options.handles_to_inherit.push_back(shm.region.GetPlatformHandle());
1428 #elif defined(OS_MAC)
1429 options.mach_ports_for_rendezvous.insert(
1430 std::make_pair('fldt', MachRendezvousPort{shm.region.GetPlatformHandle(),
1431 MACH_MSG_TYPE_COPY_SEND}));
1432 #elif defined(OS_POSIX)
1433
1434 #if defined(OS_ANDROID)
1435 int shm_fd = shm.region.GetPlatformHandle();
1436 #else
1437 int shm_fd = shm.region.GetPlatformHandle().fd;
1438 #endif // defined(OS_ANDROID)
1439
1440 // Pick an arbitrary FD number to use for the shmem FD in the child.
1441 options.fds_to_remap.emplace_back(std::make_pair(shm_fd, 42));
1442 #endif // defined(OS_POSIX)
1443 CommandLine cmd_line = GetMultiProcessTestChildBaseCommandLine();
1444 cmd_line.AppendSwitchASCII("field_trials", serialized);
1445 cmd_line.AppendSwitchASCII("guid", shm.region.GetGUID().ToString());
1446
1447 Process process = SpawnMultiProcessTestChild(
1448 "SerializeSharedMemoryRegionMetadata", cmd_line, options);
1449
1450 int exit_code;
1451 EXPECT_TRUE(WaitForMultiprocessTestChildExit(
1452 process, TestTimeouts::action_timeout(), &exit_code));
1453 EXPECT_EQ(0, exit_code);
1454 }
1455 #endif // !defined(OS_NACL) && !defined(OS_IOS) && !defined(OS_FUCHSIA)
1456
1457 // Verify that the field trial shared memory handle is really read-only, and
1458 // does not allow writable mappings. Test disabled on NaCl, Fuchsia, and Mac,
1459 // which don't support/implement shared memory configuration. For Fuchsia, see
1460 // crbug.com/752368
1461 #if !defined(OS_NACL) && !defined(OS_FUCHSIA) && !defined(OS_MAC)
TEST_F(FieldTrialListTest,CheckReadOnlySharedMemoryRegion)1462 TEST_F(FieldTrialListTest, CheckReadOnlySharedMemoryRegion) {
1463 FieldTrialList field_trial_list(nullptr);
1464 FieldTrialList::CreateFieldTrial("Trial1", "Group1");
1465
1466 FieldTrialList::InstantiateFieldTrialAllocatorIfNeeded();
1467
1468 base::ReadOnlySharedMemoryRegion region =
1469 FieldTrialList::DuplicateFieldTrialSharedMemoryForTesting();
1470 ASSERT_TRUE(region.IsValid());
1471
1472 ASSERT_TRUE(CheckReadOnlyPlatformSharedMemoryRegionForTesting(
1473 base::ReadOnlySharedMemoryRegion::TakeHandleForSerialization(
1474 std::move(region))));
1475 }
1476 #endif // !OS_NACL && !OS_FUCHSIA && !OS_MAC
1477
TEST_F(FieldTrialTest,TestAllParamsToString)1478 TEST_F(FieldTrialTest, TestAllParamsToString) {
1479 std::string exptected_output = "t1.g1:p1/v1/p2/v2";
1480
1481 // Create study with one group and two params.
1482 std::map<std::string, std::string> params;
1483 params["p1"] = "v1";
1484 params["p2"] = "v2";
1485 FieldTrialParamAssociator::GetInstance()->AssociateFieldTrialParams(
1486 "t1", "g1", params);
1487 EXPECT_EQ(
1488 "", FieldTrialList::AllParamsToString(false, &MockEscapeQueryParamValue));
1489
1490 scoped_refptr<FieldTrial> trial1 =
1491 CreateFieldTrial("t1", 100, "Default", nullptr);
1492 trial1->AppendGroup("g1", 100);
1493 trial1->group();
1494 EXPECT_EQ(exptected_output, FieldTrialList::AllParamsToString(
1495 false, &MockEscapeQueryParamValue));
1496
1497 // Create study with two groups and params that don't belog to the assigned
1498 // group. This should be in the output.
1499 FieldTrialParamAssociator::GetInstance()->AssociateFieldTrialParams(
1500 "t2", "g2", params);
1501 scoped_refptr<FieldTrial> trial2 =
1502 CreateFieldTrial("t2", 100, "Default", nullptr);
1503 trial2->AppendGroup("g1", 100);
1504 trial2->AppendGroup("g2", 0);
1505 trial2->group();
1506 EXPECT_EQ(exptected_output, FieldTrialList::AllParamsToString(
1507 false, &MockEscapeQueryParamValue));
1508 }
1509
1510 } // namespace base
1511