about summary refs log blame commit diff
path: root/absl/strings/str_split_test.cc
blob: 500f3cbc37895ecbf718fefbf5ab9f0051ae573a (plain) (tree)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871















                                                                           
                
                           



                 
                      







                                                                    








































































































































                                                                                    











                                                                     


















































































































































































































































































































































































































































































































































































































































































































                                                                                          
                                    


                                                                









                                                              
















                                                                             
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "absl/strings/str_split.h"

#include <deque>
#include <initializer_list>
#include <list>
#include <map>
#include <memory>
#include <string>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/base/dynamic_annotations.h"  // for RunningOnValgrind
#include "absl/base/macros.h"
#include "absl/strings/numbers.h"

namespace {

using ::testing::ElementsAre;
using ::testing::Pair;
using ::testing::UnorderedElementsAre;

// This tests the overall split API, which is made up of the absl::StrSplit()
// function and the Delimiter objects in the absl:: namespace.
// This TEST macro is outside of any namespace to require full specification of
// namespaces just like callers will need to use.
TEST(Split, APIExamples) {
  {
    // Passes std::string delimiter. Assumes the default of Literal.
    std::vector<std::string> v = absl::StrSplit("a,b,c", ',');
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));

    // Equivalent to...
    using absl::ByString;
    v = absl::StrSplit("a,b,c", ByString(","));
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));

    // Equivalent to...
    EXPECT_THAT(absl::StrSplit("a,b,c", ByString(",")),
                ElementsAre("a", "b", "c"));
  }

  {
    // Same as above, but using a single character as the delimiter.
    std::vector<std::string> v = absl::StrSplit("a,b,c", ',');
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));

    // Equivalent to...
    using absl::ByChar;
    v = absl::StrSplit("a,b,c", ByChar(','));
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
  }

  {
    // Same as above, but using std::string
    std::vector<std::string> v = absl::StrSplit("a,b,c", ',');
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));

    // Equivalent to...
    using absl::ByChar;
    v = absl::StrSplit("a,b,c", ByChar(','));
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
  }

  {
    // Uses the Literal std::string "=>" as the delimiter.
    const std::vector<std::string> v = absl::StrSplit("a=>b=>c", "=>");
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
  }

  {
    // The substrings are returned as string_views, eliminating copying.
    std::vector<absl::string_view> v = absl::StrSplit("a,b,c", ',');
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
  }

  {
    // Leading and trailing empty substrings.
    std::vector<std::string> v = absl::StrSplit(",a,b,c,", ',');
    EXPECT_THAT(v, ElementsAre("", "a", "b", "c", ""));
  }

  {
    // Splits on a delimiter that is not found.
    std::vector<std::string> v = absl::StrSplit("abc", ',');
    EXPECT_THAT(v, ElementsAre("abc"));
  }

  {
    // Splits the input std::string into individual characters by using an empty
    // std::string as the delimiter.
    std::vector<std::string> v = absl::StrSplit("abc", "");
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
  }

  {
    // Splits std::string data with embedded NUL characters, using NUL as the
    // delimiter. A simple delimiter of "\0" doesn't work because strlen() will
    // say that's the empty std::string when constructing the absl::string_view
    // delimiter. Instead, a non-empty std::string containing NUL can be used as the
    // delimiter.
    std::string embedded_nulls("a\0b\0c", 5);
    std::string null_delim("\0", 1);
    std::vector<std::string> v = absl::StrSplit(embedded_nulls, null_delim);
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
  }

  {
    // Stores first two split strings as the members in a std::pair.
    std::pair<std::string, std::string> p = absl::StrSplit("a,b,c", ',');
    EXPECT_EQ("a", p.first);
    EXPECT_EQ("b", p.second);
    // "c" is omitted because std::pair can hold only two elements.
  }

  {
    // Results stored in std::set<std::string>
    std::set<std::string> v = absl::StrSplit("a,b,c,a,b,c,a,b,c", ',');
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
  }

  {
    // Uses a non-const char* delimiter.
    char a[] = ",";
    char* d = a + 0;
    std::vector<std::string> v = absl::StrSplit("a,b,c", d);
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
  }

  {
    // Results split using either of , or ;
    using absl::ByAnyChar;
    std::vector<std::string> v = absl::StrSplit("a,b;c", ByAnyChar(",;"));
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
  }

  {
    // Uses the SkipWhitespace predicate.
    using absl::SkipWhitespace;
    std::vector<std::string> v = absl::StrSplit("a, ,,b,", ',', SkipWhitespace());
    EXPECT_THAT(v, ElementsAre("a", "b"));
  }

  {
    // Uses the ByLength delimiter.
    using absl::ByLength;
    std::vector<std::string> v = absl::StrSplit("abcdefg", ByLength(3));
    EXPECT_THAT(v, ElementsAre("abc", "def", "g"));
  }

  {
    // Different forms of initialization / conversion.
    std::vector<std::string> v1 = absl::StrSplit("a,b,c", ',');
    EXPECT_THAT(v1, ElementsAre("a", "b", "c"));
    std::vector<std::string> v2(absl::StrSplit("a,b,c", ','));
    EXPECT_THAT(v2, ElementsAre("a", "b", "c"));
    auto v3 = std::vector<std::string>(absl::StrSplit("a,b,c", ','));
    EXPECT_THAT(v3, ElementsAre("a", "b", "c"));
    v3 = absl::StrSplit("a,b,c", ',');
    EXPECT_THAT(v3, ElementsAre("a", "b", "c"));
  }

  {
    // Results stored in a std::map.
    std::map<std::string, std::string> m = absl::StrSplit("a,1,b,2,a,3", ',');
    EXPECT_EQ(2, m.size());
    EXPECT_EQ("3", m["a"]);
    EXPECT_EQ("2", m["b"]);
  }

  {
    // Results stored in a std::multimap.
    std::multimap<std::string, std::string> m = absl::StrSplit("a,1,b,2,a,3", ',');
    EXPECT_EQ(3, m.size());
    auto it = m.find("a");
    EXPECT_EQ("1", it->second);
    ++it;
    EXPECT_EQ("3", it->second);
    it = m.find("b");
    EXPECT_EQ("2", it->second);
  }

  {
    // Demonstrates use in a range-based for loop in C++11.
    std::string s = "x,x,x,x,x,x,x";
    for (absl::string_view sp : absl::StrSplit(s, ',')) {
      EXPECT_EQ("x", sp);
    }
  }

  {
    // Demonstrates use with a Predicate in a range-based for loop.
    using absl::SkipWhitespace;
    std::string s = " ,x,,x,,x,x,x,,";
    for (absl::string_view sp : absl::StrSplit(s, ',', SkipWhitespace())) {
      EXPECT_EQ("x", sp);
    }
  }

  {
    // Demonstrates a "smart" split to std::map using two separate calls to
    // absl::StrSplit. One call to split the records, and another call to split
    // the keys and values. This also uses the Limit delimiter so that the
    // std::string "a=b=c" will split to "a" -> "b=c".
    std::map<std::string, std::string> m;
    for (absl::string_view sp : absl::StrSplit("a=b=c,d=e,f=,g", ',')) {
      m.insert(absl::StrSplit(sp, absl::MaxSplits('=', 1)));
    }
    EXPECT_EQ("b=c", m.find("a")->second);
    EXPECT_EQ("e", m.find("d")->second);
    EXPECT_EQ("", m.find("f")->second);
    EXPECT_EQ("", m.find("g")->second);
  }
}

//
// Tests for SplitIterator
//

TEST(SplitIterator, Basics) {
  auto splitter = absl::StrSplit("a,b", ',');
  auto it = splitter.begin();
  auto end = splitter.end();

  EXPECT_NE(it, end);
  EXPECT_EQ("a", *it);  // tests dereference
  ++it;  // tests preincrement
  EXPECT_NE(it, end);
  EXPECT_EQ("b", std::string(it->data(), it->size()));  // tests dereference as ptr
  it++;  // tests postincrement
  EXPECT_EQ(it, end);
}

// Simple Predicate to skip a particular std::string.
class Skip {
 public:
  explicit Skip(const std::string& s) : s_(s) {}
  bool operator()(absl::string_view sp) { return sp != s_; }

 private:
  std::string s_;
};

TEST(SplitIterator, Predicate) {
  auto splitter = absl::StrSplit("a,b,c", ',', Skip("b"));
  auto it = splitter.begin();
  auto end = splitter.end();

  EXPECT_NE(it, end);
  EXPECT_EQ("a", *it);  // tests dereference
  ++it;  // tests preincrement -- "b" should be skipped here.
  EXPECT_NE(it, end);
  EXPECT_EQ("c", std::string(it->data(), it->size()));  // tests dereference as ptr
  it++;  // tests postincrement
  EXPECT_EQ(it, end);
}

TEST(SplitIterator, EdgeCases) {
  // Expected input and output, assuming a delimiter of ','
  struct {
    std::string in;
    std::vector<std::string> expect;
  } specs[] = {
    {"", {""}},
    {"foo", {"foo"}},
    {",", {"", ""}},
    {",foo", {"", "foo"}},
    {"foo,", {"foo", ""}},
    {",foo,", {"", "foo", ""}},
    {"foo,bar", {"foo", "bar"}},
  };

  for (const auto& spec : specs) {
    SCOPED_TRACE(spec.in);
    auto splitter = absl::StrSplit(spec.in, ',');
    auto it = splitter.begin();
    auto end = splitter.end();
    for (const auto& expected : spec.expect) {
      EXPECT_NE(it, end);
      EXPECT_EQ(expected, *it++);
    }
    EXPECT_EQ(it, end);
  }
}

TEST(Splitter, Const) {
  const auto splitter = absl::StrSplit("a,b,c", ',');
  EXPECT_THAT(splitter, ElementsAre("a", "b", "c"));
}

TEST(Split, EmptyAndNull) {
  // Attention: Splitting a null absl::string_view is different than splitting
  // an empty absl::string_view even though both string_views are considered
  // equal. This behavior is likely surprising and undesirable. However, to
  // maintain backward compatibility, there is a small "hack" in
  // str_split_internal.h that preserves this behavior. If that behavior is ever
  // changed/fixed, this test will need to be updated.
  EXPECT_THAT(absl::StrSplit(absl::string_view(""), '-'), ElementsAre(""));
  EXPECT_THAT(absl::StrSplit(absl::string_view(), '-'), ElementsAre());
}

TEST(SplitIterator, EqualityAsEndCondition) {
  auto splitter = absl::StrSplit("a,b,c", ',');
  auto it = splitter.begin();
  auto it2 = it;

  // Increments it2 twice to point to "c" in the input text.
  ++it2;
  ++it2;
  EXPECT_EQ("c", *it2);

  // This test uses a non-end SplitIterator as the terminating condition in a
  // for loop. This relies on SplitIterator equality for non-end SplitIterators
  // working correctly. At this point it2 points to "c", and we use that as the
  // "end" condition in this test.
  std::vector<absl::string_view> v;
  for (; it != it2; ++it) {
    v.push_back(*it);
  }
  EXPECT_THAT(v, ElementsAre("a", "b"));
}

//
// Tests for Splitter
//

TEST(Splitter, RangeIterators) {
  auto splitter = absl::StrSplit("a,b,c", ',');
  std::vector<absl::string_view> output;
  for (const absl::string_view p : splitter) {
    output.push_back(p);
  }
  EXPECT_THAT(output, ElementsAre("a", "b", "c"));
}

// Some template functions for use in testing conversion operators
template <typename ContainerType, typename Splitter>
void TestConversionOperator(const Splitter& splitter) {
  ContainerType output = splitter;
  EXPECT_THAT(output, UnorderedElementsAre("a", "b", "c", "d"));
}

template <typename MapType, typename Splitter>
void TestMapConversionOperator(const Splitter& splitter) {
  MapType m = splitter;
  EXPECT_THAT(m, UnorderedElementsAre(Pair("a", "b"), Pair("c", "d")));
}

template <typename FirstType, typename SecondType, typename Splitter>
void TestPairConversionOperator(const Splitter& splitter) {
  std::pair<FirstType, SecondType> p = splitter;
  EXPECT_EQ(p, (std::pair<FirstType, SecondType>("a", "b")));
}

TEST(Splitter, ConversionOperator) {
  auto splitter = absl::StrSplit("a,b,c,d", ',');

  TestConversionOperator<std::vector<absl::string_view>>(splitter);
  TestConversionOperator<std::vector<std::string>>(splitter);
  TestConversionOperator<std::list<absl::string_view>>(splitter);
  TestConversionOperator<std::list<std::string>>(splitter);
  TestConversionOperator<std::deque<absl::string_view>>(splitter);
  TestConversionOperator<std::deque<std::string>>(splitter);
  TestConversionOperator<std::set<absl::string_view>>(splitter);
  TestConversionOperator<std::set<std::string>>(splitter);
  TestConversionOperator<std::multiset<absl::string_view>>(splitter);
  TestConversionOperator<std::multiset<std::string>>(splitter);
  TestConversionOperator<std::unordered_set<std::string>>(splitter);

  // Tests conversion to map-like objects.

  TestMapConversionOperator<std::map<absl::string_view, absl::string_view>>(
      splitter);
  TestMapConversionOperator<std::map<absl::string_view, std::string>>(splitter);
  TestMapConversionOperator<std::map<std::string, absl::string_view>>(splitter);
  TestMapConversionOperator<std::map<std::string, std::string>>(splitter);
  TestMapConversionOperator<
      std::multimap<absl::string_view, absl::string_view>>(splitter);
  TestMapConversionOperator<std::multimap<absl::string_view, std::string>>(splitter);
  TestMapConversionOperator<std::multimap<std::string, absl::string_view>>(splitter);
  TestMapConversionOperator<std::multimap<std::string, std::string>>(splitter);
  TestMapConversionOperator<std::unordered_map<std::string, std::string>>(splitter);

  // Tests conversion to std::pair

  TestPairConversionOperator<absl::string_view, absl::string_view>(splitter);
  TestPairConversionOperator<absl::string_view, std::string>(splitter);
  TestPairConversionOperator<std::string, absl::string_view>(splitter);
  TestPairConversionOperator<std::string, std::string>(splitter);
}

// A few additional tests for conversion to std::pair. This conversion is
// different from others because a std::pair always has exactly two elements:
// .first and .second. The split has to work even when the split has
// less-than, equal-to, and more-than 2 strings.
TEST(Splitter, ToPair) {
  {
    // Empty std::string
    std::pair<std::string, std::string> p = absl::StrSplit("", ',');
    EXPECT_EQ("", p.first);
    EXPECT_EQ("", p.second);
  }

  {
    // Only first
    std::pair<std::string, std::string> p = absl::StrSplit("a", ',');
    EXPECT_EQ("a", p.first);
    EXPECT_EQ("", p.second);
  }

  {
    // Only second
    std::pair<std::string, std::string> p = absl::StrSplit(",b", ',');
    EXPECT_EQ("", p.first);
    EXPECT_EQ("b", p.second);
  }

  {
    // First and second.
    std::pair<std::string, std::string> p = absl::StrSplit("a,b", ',');
    EXPECT_EQ("a", p.first);
    EXPECT_EQ("b", p.second);
  }

  {
    // First and second and then more stuff that will be ignored.
    std::pair<std::string, std::string> p = absl::StrSplit("a,b,c", ',');
    EXPECT_EQ("a", p.first);
    EXPECT_EQ("b", p.second);
    // "c" is omitted.
  }
}

TEST(Splitter, Predicates) {
  static const char kTestChars[] = ",a, ,b,";
  using absl::AllowEmpty;
  using absl::SkipEmpty;
  using absl::SkipWhitespace;

  {
    // No predicate. Does not skip empties.
    auto splitter = absl::StrSplit(kTestChars, ',');
    std::vector<std::string> v = splitter;
    EXPECT_THAT(v, ElementsAre("", "a", " ", "b", ""));
  }

  {
    // Allows empty strings. Same behavior as no predicate at all.
    auto splitter = absl::StrSplit(kTestChars, ',', AllowEmpty());
    std::vector<std::string> v_allowempty = splitter;
    EXPECT_THAT(v_allowempty, ElementsAre("", "a", " ", "b", ""));

    // Ensures AllowEmpty equals the behavior with no predicate.
    auto splitter_nopredicate = absl::StrSplit(kTestChars, ',');
    std::vector<std::string> v_nopredicate = splitter_nopredicate;
    EXPECT_EQ(v_allowempty, v_nopredicate);
  }

  {
    // Skips empty strings.
    auto splitter = absl::StrSplit(kTestChars, ',', SkipEmpty());
    std::vector<std::string> v = splitter;
    EXPECT_THAT(v, ElementsAre("a", " ", "b"));
  }

  {
    // Skips empty and all-whitespace strings.
    auto splitter = absl::StrSplit(kTestChars, ',', SkipWhitespace());
    std::vector<std::string> v = splitter;
    EXPECT_THAT(v, ElementsAre("a", "b"));
  }
}

//
// Tests for StrSplit()
//

TEST(Split, Basics) {
  {
    // Doesn't really do anything useful because the return value is ignored,
    // but it should work.
    absl::StrSplit("a,b,c", ',');
  }

  {
    std::vector<absl::string_view> v = absl::StrSplit("a,b,c", ',');
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
  }

  {
    std::vector<std::string> v = absl::StrSplit("a,b,c", ',');
    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
  }

  {
    // Ensures that assignment works. This requires a little extra work with
    // C++11 because of overloads with initializer_list.
    std::vector<std::string> v;
    v = absl::StrSplit("a,b,c", ',');

    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    std::map<std::string, std::string> m;
    m = absl::StrSplit("a,b,c", ',');
    EXPECT_EQ(2, m.size());
    std::unordered_map<std::string, std::string> hm;
    hm = absl::StrSplit("a,b,c", ',');
    EXPECT_EQ(2, hm.size());
  }
}

absl::string_view ReturnStringView() { return "Hello World"; }
const char* ReturnConstCharP() { return "Hello World"; }
char* ReturnCharP() { return const_cast<char*>("Hello World"); }

TEST(Split, AcceptsCertainTemporaries) {
  std::vector<std::string> v;
  v = absl::StrSplit(ReturnStringView(), ' ');
  EXPECT_THAT(v, ElementsAre("Hello", "World"));
  v = absl::StrSplit(ReturnConstCharP(), ' ');
  EXPECT_THAT(v, ElementsAre("Hello", "World"));
  v = absl::StrSplit(ReturnCharP(), ' ');
  EXPECT_THAT(v, ElementsAre("Hello", "World"));
}

TEST(Split, Temporary) {
  // Use a std::string longer than the small-std::string-optimization length, so that when
  // the temporary is destroyed, if the splitter keeps a reference to the
  // std::string's contents, it'll reference freed memory instead of just dead
  // on-stack memory.
  const char input[] = "a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u";
  EXPECT_LT(sizeof(std::string), ABSL_ARRAYSIZE(input))
      << "Input should be larger than fits on the stack.";

  // This happens more often in C++11 as part of a range-based for loop.
  auto splitter = absl::StrSplit(std::string(input), ',');
  std::string expected = "a";
  for (absl::string_view letter : splitter) {
    EXPECT_EQ(expected, letter);
    ++expected[0];
  }
  EXPECT_EQ("v", expected);

  // This happens more often in C++11 as part of a range-based for loop.
  auto std_splitter = absl::StrSplit(std::string(input), ',');
  expected = "a";
  for (absl::string_view letter : std_splitter) {
    EXPECT_EQ(expected, letter);
    ++expected[0];
  }
  EXPECT_EQ("v", expected);
}

template <typename T>
static std::unique_ptr<T> CopyToHeap(const T& value) {
  return std::unique_ptr<T>(new T(value));
}

TEST(Split, LvalueCaptureIsCopyable) {
  std::string input = "a,b";
  auto heap_splitter = CopyToHeap(absl::StrSplit(input, ','));
  auto stack_splitter = *heap_splitter;
  heap_splitter.reset();
  std::vector<std::string> result = stack_splitter;
  EXPECT_THAT(result, testing::ElementsAre("a", "b"));
}

TEST(Split, TemporaryCaptureIsCopyable) {
  auto heap_splitter = CopyToHeap(absl::StrSplit(std::string("a,b"), ','));
  auto stack_splitter = *heap_splitter;
  heap_splitter.reset();
  std::vector<std::string> result = stack_splitter;
  EXPECT_THAT(result, testing::ElementsAre("a", "b"));
}

TEST(Split, SplitterIsCopyableAndMoveable) {
  auto a = absl::StrSplit("foo", '-');

  // Ensures that the following expressions compile.
  auto b = a;             // Copy construct
  auto c = std::move(a);  // Move construct
  b = c;                  // Copy assign
  c = std::move(b);       // Move assign

  EXPECT_THAT(c, ElementsAre("foo"));
}

TEST(Split, StringDelimiter) {
  {
    std::vector<absl::string_view> v = absl::StrSplit("a,b", ',');
    EXPECT_THAT(v, ElementsAre("a", "b"));
  }

  {
    std::vector<absl::string_view> v = absl::StrSplit("a,b", std::string(","));
    EXPECT_THAT(v, ElementsAre("a", "b"));
  }

  {
    std::vector<absl::string_view> v =
        absl::StrSplit("a,b", absl::string_view(","));
    EXPECT_THAT(v, ElementsAre("a", "b"));
  }
}

TEST(Split, UTF8) {
  // Tests splitting utf8 strings and utf8 delimiters.
  {
    // A utf8 input std::string with an ascii delimiter.
    std::vector<absl::string_view> v = absl::StrSplit("a,κόσμε", ',');
    EXPECT_THAT(v, ElementsAre("a", "κόσμε"));
  }

  {
    // A utf8 input std::string and a utf8 delimiter.
    std::vector<absl::string_view> v = absl::StrSplit("a,κόσμε,b", ",κόσμε,");
    EXPECT_THAT(v, ElementsAre("a", "b"));
  }

  {
    // A utf8 input std::string and ByAnyChar with ascii chars.
    std::vector<absl::string_view> v =
        absl::StrSplit("Foo hällo th丞re", absl::ByAnyChar(" \t"));
    EXPECT_THAT(v, ElementsAre("Foo", "hällo", "th丞re"));
  }
}

TEST(Split, EmptyStringDelimiter) {
  {
    std::vector<std::string> v = absl::StrSplit("", "");
    EXPECT_THAT(v, ElementsAre(""));
  }

  {
    std::vector<std::string> v = absl::StrSplit("a", "");
    EXPECT_THAT(v, ElementsAre("a"));
  }

  {
    std::vector<std::string> v = absl::StrSplit("ab", "");
    EXPECT_THAT(v, ElementsAre("a", "b"));
  }

  {
    std::vector<std::string> v = absl::StrSplit("a b", "");
    EXPECT_THAT(v, ElementsAre("a", " ", "b"));
  }
}

TEST(Split, SubstrDelimiter) {
  std::vector<absl::string_view> results;
  absl::string_view delim("//");

  results = absl::StrSplit("", delim);
  EXPECT_THAT(results, ElementsAre(""));

  results = absl::StrSplit("//", delim);
  EXPECT_THAT(results, ElementsAre("", ""));

  results = absl::StrSplit("ab", delim);
  EXPECT_THAT(results, ElementsAre("ab"));

  results = absl::StrSplit("ab//", delim);
  EXPECT_THAT(results, ElementsAre("ab", ""));

  results = absl::StrSplit("ab/", delim);
  EXPECT_THAT(results, ElementsAre("ab/"));

  results = absl::StrSplit("a/b", delim);
  EXPECT_THAT(results, ElementsAre("a/b"));

  results = absl::StrSplit("a//b", delim);
  EXPECT_THAT(results, ElementsAre("a", "b"));

  results = absl::StrSplit("a///b", delim);
  EXPECT_THAT(results, ElementsAre("a", "/b"));

  results = absl::StrSplit("a////b", delim);
  EXPECT_THAT(results, ElementsAre("a", "", "b"));
}

TEST(Split, EmptyResults) {
  std::vector<absl::string_view> results;

  results = absl::StrSplit("", '#');
  EXPECT_THAT(results, ElementsAre(""));

  results = absl::StrSplit("#", '#');
  EXPECT_THAT(results, ElementsAre("", ""));

  results = absl::StrSplit("#cd", '#');
  EXPECT_THAT(results, ElementsAre("", "cd"));

  results = absl::StrSplit("ab#cd#", '#');
  EXPECT_THAT(results, ElementsAre("ab", "cd", ""));

  results = absl::StrSplit("ab##cd", '#');
  EXPECT_THAT(results, ElementsAre("ab", "", "cd"));

  results = absl::StrSplit("ab##", '#');
  EXPECT_THAT(results, ElementsAre("ab", "", ""));

  results = absl::StrSplit("ab#ab#", '#');
  EXPECT_THAT(results, ElementsAre("ab", "ab", ""));

  results = absl::StrSplit("aaaa", 'a');
  EXPECT_THAT(results, ElementsAre("", "", "", "", ""));

  results = absl::StrSplit("", '#', absl::SkipEmpty());
  EXPECT_THAT(results, ElementsAre());
}

template <typename Delimiter>
static bool IsFoundAtStartingPos(absl::string_view text, Delimiter d,
                                 size_t starting_pos, int expected_pos) {
  absl::string_view found = d.Find(text, starting_pos);
  return found.data() != text.end() &&
         expected_pos == found.data() - text.data();
}

// Helper function for testing Delimiter objects. Returns true if the given
// Delimiter is found in the given std::string at the given position. This function
// tests two cases:
//   1. The actual text given, staring at position 0
//   2. The text given with leading padding that should be ignored
template <typename Delimiter>
static bool IsFoundAt(absl::string_view text, Delimiter d, int expected_pos) {
  const std::string leading_text = ",x,y,z,";
  return IsFoundAtStartingPos(text, d, 0, expected_pos) &&
         IsFoundAtStartingPos(leading_text + std::string(text), d,
                              leading_text.length(),
                              expected_pos + leading_text.length());
}

//
// Tests for Literal
//

// Tests using any delimiter that represents a single comma.
template <typename Delimiter>
void TestComma(Delimiter d) {
  EXPECT_TRUE(IsFoundAt(",", d, 0));
  EXPECT_TRUE(IsFoundAt("a,", d, 1));
  EXPECT_TRUE(IsFoundAt(",b", d, 0));
  EXPECT_TRUE(IsFoundAt("a,b", d, 1));
  EXPECT_TRUE(IsFoundAt("a,b,", d, 1));
  EXPECT_TRUE(IsFoundAt("a,b,c", d, 1));
  EXPECT_FALSE(IsFoundAt("", d, -1));
  EXPECT_FALSE(IsFoundAt(" ", d, -1));
  EXPECT_FALSE(IsFoundAt("a", d, -1));
  EXPECT_FALSE(IsFoundAt("a b c", d, -1));
  EXPECT_FALSE(IsFoundAt("a;b;c", d, -1));
  EXPECT_FALSE(IsFoundAt(";", d, -1));
}

TEST(Delimiter, Literal) {
  using absl::ByString;
  TestComma(ByString(","));

  // Works as named variable.
  ByString comma_string(",");
  TestComma(comma_string);

  // The first occurrence of empty std::string ("") in a std::string is at position 0.
  // There is a test below that demonstrates this for absl::string_view::find().
  // If the ByString delimiter returned position 0 for this, there would
  // be an infinite loop in the SplitIterator code. To avoid this, empty std::string
  // is a special case in that it always returns the item at position 1.
  absl::string_view abc("abc");
  EXPECT_EQ(0, abc.find(""));  // "" is found at position 0
  ByString empty("");
  EXPECT_FALSE(IsFoundAt("", empty, 0));
  EXPECT_FALSE(IsFoundAt("a", empty, 0));
  EXPECT_TRUE(IsFoundAt("ab", empty, 1));
  EXPECT_TRUE(IsFoundAt("abc", empty, 1));
}

TEST(Split, ByChar) {
  using absl::ByChar;
  TestComma(ByChar(','));

  // Works as named variable.
  ByChar comma_char(',');
  TestComma(comma_char);
}

//
// Tests for ByAnyChar
//

TEST(Delimiter, ByAnyChar) {
  using absl::ByAnyChar;
  ByAnyChar one_delim(",");
  // Found
  EXPECT_TRUE(IsFoundAt(",", one_delim, 0));
  EXPECT_TRUE(IsFoundAt("a,", one_delim, 1));
  EXPECT_TRUE(IsFoundAt("a,b", one_delim, 1));
  EXPECT_TRUE(IsFoundAt(",b", one_delim, 0));
  // Not found
  EXPECT_FALSE(IsFoundAt("", one_delim, -1));
  EXPECT_FALSE(IsFoundAt(" ", one_delim, -1));
  EXPECT_FALSE(IsFoundAt("a", one_delim, -1));
  EXPECT_FALSE(IsFoundAt("a;b;c", one_delim, -1));
  EXPECT_FALSE(IsFoundAt(";", one_delim, -1));

  ByAnyChar two_delims(",;");
  // Found
  EXPECT_TRUE(IsFoundAt(",", two_delims, 0));
  EXPECT_TRUE(IsFoundAt(";", two_delims, 0));
  EXPECT_TRUE(IsFoundAt(",;", two_delims, 0));
  EXPECT_TRUE(IsFoundAt(";,", two_delims, 0));
  EXPECT_TRUE(IsFoundAt(",;b", two_delims, 0));
  EXPECT_TRUE(IsFoundAt(";,b", two_delims, 0));
  EXPECT_TRUE(IsFoundAt("a;,", two_delims, 1));
  EXPECT_TRUE(IsFoundAt("a,;", two_delims, 1));
  EXPECT_TRUE(IsFoundAt("a;,b", two_delims, 1));
  EXPECT_TRUE(IsFoundAt("a,;b", two_delims, 1));
  // Not found
  EXPECT_FALSE(IsFoundAt("", two_delims, -1));
  EXPECT_FALSE(IsFoundAt(" ", two_delims, -1));
  EXPECT_FALSE(IsFoundAt("a", two_delims, -1));
  EXPECT_FALSE(IsFoundAt("a=b=c", two_delims, -1));
  EXPECT_FALSE(IsFoundAt("=", two_delims, -1));

  // ByAnyChar behaves just like ByString when given a delimiter of empty
  // std::string. That is, it always returns a zero-length absl::string_view
  // referring to the item at position 1, not position 0.
  ByAnyChar empty("");
  EXPECT_FALSE(IsFoundAt("", empty, 0));
  EXPECT_FALSE(IsFoundAt("a", empty, 0));
  EXPECT_TRUE(IsFoundAt("ab", empty, 1));
  EXPECT_TRUE(IsFoundAt("abc", empty, 1));
}

//
// Tests for ByLength
//

TEST(Delimiter, ByLength) {
  using absl::ByLength;

  ByLength four_char_delim(4);

  // Found
  EXPECT_TRUE(IsFoundAt("abcde", four_char_delim, 4));
  EXPECT_TRUE(IsFoundAt("abcdefghijklmnopqrstuvwxyz", four_char_delim, 4));
  EXPECT_TRUE(IsFoundAt("a b,c\nd", four_char_delim, 4));
  // Not found
  EXPECT_FALSE(IsFoundAt("", four_char_delim, 0));
  EXPECT_FALSE(IsFoundAt("a", four_char_delim, 0));
  EXPECT_FALSE(IsFoundAt("ab", four_char_delim, 0));
  EXPECT_FALSE(IsFoundAt("abc", four_char_delim, 0));
  EXPECT_FALSE(IsFoundAt("abcd", four_char_delim, 0));
}

TEST(Split, WorksWithLargeStrings) {
  if (sizeof(size_t) > 4) {
    std::string s((uint32_t{1} << 31) + 1, 'x');  // 2G + 1 byte
    s.back() = '-';
    std::vector<absl::string_view> v = absl::StrSplit(s, '-');
    EXPECT_EQ(2, v.size());
    // The first element will contain 2G of 'x's.
    // testing::StartsWith is too slow with a 2G std::string.
    EXPECT_EQ('x', v[0][0]);
    EXPECT_EQ('x', v[0][1]);
    EXPECT_EQ('x', v[0][3]);
    EXPECT_EQ("", v[1]);
  }
}

TEST(SplitInternalTest, TypeTraits) {
  EXPECT_FALSE(absl::strings_internal::HasMappedType<int>::value);
  EXPECT_TRUE(
      (absl::strings_internal::HasMappedType<std::map<int, int>>::value));
  EXPECT_FALSE(absl::strings_internal::HasValueType<int>::value);
  EXPECT_TRUE(
      (absl::strings_internal::HasValueType<std::map<int, int>>::value));
  EXPECT_FALSE(absl::strings_internal::HasConstIterator<int>::value);
  EXPECT_TRUE(
      (absl::strings_internal::HasConstIterator<std::map<int, int>>::value));
  EXPECT_FALSE(absl::strings_internal::IsInitializerList<int>::value);
  EXPECT_TRUE((absl::strings_internal::IsInitializerList<
               std::initializer_list<int>>::value));
}

}  // namespace